Merge remote-tracking branch 'upstream/develop' into develop

Conflicts:
	user_guide_src/source/changelog.rst

Signed-off-by: Jonathon Hill <jhill@brandmovers.com>

79 files changed, 5832 insertions, 2185 deletions

diff --git a/system/database/DB.php b/system/database/DB.php
index d751325ce..f4062fa73 100644
--- a/system/database/DB.php
+++ b/system/database/DB.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Initialize the database
@@ -31,8 +32,10 @@
  * @category	Database
  * @author	EllisLab Dev Team
  * @link	http://codeigniter.com/user_guide/database/
- * @param 	string
- * @param 	bool	Determines if query builder should be used or not
+ *
+ * @param 	string|string[]	$params
+ * @param 	bool		$query_builder_override
+ *				Determines if query builder should be used or not
  */
 function &DB($params = '', $query_builder_override = NULL)
 {
@@ -47,18 +50,18 @@ function &DB($params = '', $query_builder_override = NULL)
 		}
 
 		include($file_path);
-		//make packages contain database config files
-		foreach(get_instance()->load->get_package_paths() as $path)
+		// Make packages contain database config files
+		foreach (get_instance()->load->get_package_paths() as $path)
 		{
 			if ($path !== APPPATH)
 			{
-				if (file_exists ($file_path = $path.'config/'.ENVIRONMENT.'/database.php'))
+				if (file_exists($file_path = $path.'config/'.ENVIRONMENT.'/database.php'))
 				{
-					include ($file_path);
+					include($file_path);
 				}
-				elseif ( file_exists ($file_path = $path.'config/database.php'))
+				elseif (file_exists($file_path = $path.'config/database.php'))
 				{
-					include ($file_path);
+					include($file_path);
 				}
 			}
 		}
@@ -82,12 +85,12 @@ function &DB($params = '', $query_builder_override = NULL)
 	}
 	elseif (is_string($params))
 	{
-
-		/* parse the URL from the DSN string
-		 *  Database settings can be passed as discreet
-		 *  parameters or as a data source name in the first
-		 *  parameter. DSNs must have this prototype:
-		 *  $dsn = 'driver://username:password@hostname/database';
+		/**
+		 * Parse the URL from the DSN string
+		 * Database settings can be passed as discreet
+		 * parameters or as a data source name in the first
+		 * parameter. DSNs must have this prototype:
+		 * $dsn = 'driver://username:password@hostname/database';
 		 */
 		if (($dsn = @parse_url($params)) === FALSE)
 		{
@@ -103,7 +106,7 @@ function &DB($params = '', $query_builder_override = NULL)
 				'database'	=> isset($dsn['path']) ? rawurldecode(substr($dsn['path'], 1)) : ''
 			);
 
-		// were additional config items set?
+		// Were additional config items set?
 		if (isset($dsn['query']))
 		{
 			parse_str($dsn['query'], $extra);
@@ -148,11 +151,22 @@ function &DB($params = '', $query_builder_override = NULL)
 		require_once(BASEPATH.'database/DB_query_builder.php');
 		if ( ! class_exists('CI_DB'))
 		{
+			/**
+			 * CI_DB
+			 *
+			 * Acts as an alias for both CI_DB_driver and CI_DB_query_builder.
+			 *
+			 * @see	CI_DB_query_builder
+			 * @see	CI_DB_driver
+			 */
 			class CI_DB extends CI_DB_query_builder { }
 		}
 	}
 	elseif ( ! class_exists('CI_DB'))
 	{
+		/**
+	 	 * @ignore
+		 */
 		class CI_DB extends CI_DB_driver { }
 	}
 
diff --git a/system/database/DB_cache.php b/system/database/DB_cache.php
index d07c755c6..1be80c5c7 100644
--- a/system/database/DB_cache.php
+++ b/system/database/DB_cache.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Database Cache Class
@@ -34,8 +35,24 @@
  */
 class CI_DB_Cache {
 
+	/**
+	 * CI Singleton
+	 *
+	 * @var	object
+	 */
 	public $CI;
-	public $db;	// allows passing of db object so that multiple database connections and returned db objects can be supported
+
+	/**
+	 * Database object
+	 *
+	 * Allows passing of DB object so that multiple database connections
+	 * and returned DB objects can be supported.
+	 *
+	 * @var	object
+	 */
+	public $db;
+
+	// --------------------------------------------------------------------
 
 	/**
 	 * Constructor
@@ -58,7 +75,7 @@ class CI_DB_Cache {
 	/**
 	 * Set Cache Directory Path
 	 *
-	 * @param	string	the path to the cache directory
+	 * @param	string	$path	Path to the cache directory
 	 * @return	bool
 	 */
 	public function check_path($path = '')
@@ -94,7 +111,7 @@ class CI_DB_Cache {
 	 * Retrieve a cached query
 	 *
 	 * The URI being requested will become the name of the cache sub-folder.
-	 * An MD5 hash of the SQL statement will become the cache file name
+	 * An MD5 hash of the SQL statement will become the cache file name.
 	 *
 	 * @param	string	$sql
 	 * @return	string
@@ -153,8 +170,8 @@ class CI_DB_Cache {
 	/**
 	 * Delete cache files within a particular directory
 	 *
-	 * @param	string	$segment_one = ''
-	 * @param	string	$segment_two = ''
+	 * @param	string	$segment_one
+	 * @param	string	$segment_two
 	 * @return	void
 	 */
 	public function delete($segment_one = '', $segment_two = '')
@@ -182,7 +199,7 @@ class CI_DB_Cache {
 	 */
 	public function delete_all()
 	{
-		delete_files($this->db->cachedir, TRUE, 0, TRUE);
+		delete_files($this->db->cachedir, TRUE, TRUE);
 	}
 
 }
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index e8286aaa1..dfaf0e0c1 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Database Driver Class
@@ -40,60 +41,314 @@
  */
 abstract class CI_DB_driver {
 
+	/**
+	 * Data Source Name / Connect string
+	 *
+	 * @var	string
+	 */
 	public $dsn;
+
+	/**
+	 * Username
+	 *
+	 * @var	string
+	 */
 	public $username;
+
+	/**
+	 * Password
+	 *
+	 * @var	string
+	 */
 	public $password;
+
+	/**
+	 * Hostname
+	 *
+	 * @var	string
+	 */
 	public $hostname;
+
+	/**
+	 * Database name
+	 *
+	 * @var	string
+	 */
 	public $database;
+
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver		= 'mysqli';
+
+	/**
+	 * Sub-driver
+	 *
+	 * @used-by	CI_DB_pdo_driver
+	 * @var	string
+	 */
 	public $subdriver;
+
+	/**
+	 * Table prefix
+	 *
+	 * @var	string
+	 */
 	public $dbprefix		= '';
+
+	/**
+	 * Character set
+	 *
+	 * @var	string
+	 */
 	public $char_set		= 'utf8';
+
+	/**
+	 * Collation
+	 *
+	 * @var	string
+	 */
 	public $dbcollat		= 'utf8_general_ci';
-	public $autoinit		= TRUE; // Whether to automatically initialize the DB
+
+	/**
+	 * Auto-init flag
+	 *
+	 * Whether to automatically initialize the DB connection.
+	 *
+	 * @var	bool
+	 */
+	public $autoinit		= TRUE;
+
+	/**
+	 * Encryption flag/data
+	 *
+	 * @var	mixed
+	 */
 	public $encrypt			= FALSE;
+
+	/**
+	 * Swap Prefix
+	 *
+	 * @var	string
+	 */
 	public $swap_pre		= '';
+
+	/**
+	 * Database port
+	 *
+	 * @var	int
+	 */
 	public $port			= '';
+
+	/**
+	 * Persistent connection flag
+	 *
+	 * @var	bool
+	 */
 	public $pconnect		= FALSE;
+
+	/**
+	 * Connection ID
+	 *
+	 * @var	object|resource
+	 */
 	public $conn_id			= FALSE;
+
+	/**
+	 * Result ID
+	 *
+	 * @var	object|resource
+	 */
 	public $result_id		= FALSE;
+
+	/**
+	 * Debug flag
+	 *
+	 * Whether to display error messages.
+	 *
+	 * @var	bool
+	 */
 	public $db_debug		= FALSE;
+
+	/**
+	 * Benchmark time
+	 *
+	 * @var	int
+	 */
 	public $benchmark		= 0;
+
+	/**
+	 * Executed queries count
+	 *
+	 * @var	int
+	 */
 	public $query_count		= 0;
+
+	/**
+	 * Bind marker
+	 *
+	 * Character used to identify values in a prepared statement.
+	 *
+	 * @var	string
+	 */
 	public $bind_marker		= '?';
+
+	/**
+	 * Save queries flag
+	 *
+	 * Whether to keep an in-memory history of queries for debugging purposes.
+	 *
+	 * @var	bool
+	 */
 	public $save_queries		= TRUE;
+
+	/**
+	 * Queries list
+	 *
+	 * @see	CI_DB_driver::$save_queries
+	 * @var	string[]
+	 */
 	public $queries			= array();
+
+	/**
+	 * Query times
+	 *
+	 * A list of times that queries took to execute.
+	 *
+	 * @var	array
+	 */
 	public $query_times		= array();
+
+	/**
+	 * Data cache
+	 *
+	 * An internal generic value cache.
+	 *
+	 * @var	array
+	 */
 	public $data_cache		= array();
 
+	/**
+	 * Transaction enabled flag
+	 *
+	 * @var	bool
+	 */
 	public $trans_enabled		= TRUE;
+
+	/**
+	 * Strict transaction mode flag
+	 *
+	 * @var	bool
+	 */
 	public $trans_strict		= TRUE;
+
+	/**
+	 * Transaction depth level
+	 *
+	 * @var	int
+	 */
 	protected $_trans_depth		= 0;
-	protected $_trans_status	= TRUE; // Used with transactions to determine if a rollback should occur
 
+	/**
+	 * Transaction status flag
+	 *
+	 * Used with transactions to determine if a rollback should occur.
+	 *
+	 * @var	bool
+	 */
+	protected $_trans_status	= TRUE;
+
+	/**
+	 * Cache On flag
+	 *
+	 * @var	bool
+	 */
 	public $cache_on		= FALSE;
+
+	/**
+	 * Cache directory path
+	 *
+	 * @var	bool
+	 */
 	public $cachedir		= '';
+
+	/**
+	 * Cache auto-delete flag
+	 *
+	 * @var	bool
+	 */
 	public $cache_autodel		= FALSE;
-	public $CACHE; // The cache class object
 
+	/**
+	 * DB Cache object
+	 *
+	 * @see	CI_DB_cache
+	 * @var	object
+	 */
+	public $CACHE;
+
+	/**
+	 * Protect identifiers flag
+	 *
+	 * @var	bool
+	 */
 	protected $_protect_identifiers		= TRUE;
-	protected $_reserved_identifiers	= array('*'); // Identifiers that should NOT be escaped
 
-	// clause and character used for LIKE escape sequences
+	/**
+	 * List of reserved identifiers
+	 *
+	 * Identifiers that must NOT be escaped.
+	 *
+	 * @var	string[]
+	 */
+	protected $_reserved_identifiers	= array('*');
+
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
+	protected $_escape_char = '"';
+
+	/**
+	 * ESCAPE statement string
+	 *
+	 * @var	string
+	 */
 	protected $_like_escape_str = " ESCAPE '%s' ";
+
+	/**
+	 * ESCAPE character
+	 *
+	 * @var	string
+	 */
 	protected $_like_escape_chr = '!';
 
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' RAND()';
+
+	/**
+	 * COUNT string
+	 *
+	 * @used-by	CI_DB_driver::count_all()
+	 * @used-by	CI_DB_query_builder::count_all_results()
+	 *
+	 * @var	string
 	 */
 	protected $_count_string = 'SELECT COUNT(*) AS ';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -981,7 +1236,7 @@ abstract class CI_DB_driver {
 	 */
 	public function escape_identifiers($item)
 	{
-		if ($this->_escape_char === '' OR empty($item))
+		if ($this->_escape_char === '' OR empty($item) OR in_array($item, $this->_reserved_identifiers))
 		{
 			return $item;
 		}
@@ -1080,43 +1335,19 @@ abstract class CI_DB_driver {
 	 */
 	public function update_string($table, $data, $where)
 	{
-		if ($where === '')
+		if (empty($where))
 		{
 			return FALSE;
 		}
 
+		$this->where($where);
+
 		$fields = array();
 		foreach ($data as $key => $val)
 		{
 			$fields[$this->protect_identifiers($key)] = $this->escape($val);
 		}
 
-		if ( ! is_array($where))
-		{
-			$dest = array($where);
-		}
-		else
-		{
-			$dest = array();
-			foreach ($where as $key => $val)
-			{
-				$prefix = (count($dest) === 0) ? '' : ' AND ';
-				$key = $this->protect_identifiers($key);
-
-				if ($val !== '')
-				{
-					if ( ! $this->_has_operator($key))
-					{
-						$key .= ' =';
-					}
-
-					$val = ' '.$this->escape($val);
-				}
-
-				$dest[] = $prefix.$key.$val;
-			}
-		}
-
 		return $this->_update($this->protect_identifiers($table, TRUE, NULL, FALSE), $fields, $dest);
 	}
 
@@ -1198,8 +1429,7 @@ abstract class CI_DB_driver {
 	/**
 	 * Enables a native PHP function to be run, using a platform agnostic wrapper.
 	 *
-	 * @param	string	$function	the function name
-	 * @param	mixed	$param,...	optional parameters needed by the function
+	 * @param	string	$function	Function name
 	 * @return	mixed
 	 */
 	public function call_function($function)
diff --git a/system/database/DB_forge.php b/system/database/DB_forge.php
index 119d78d38..21046012a 100644
--- a/system/database/DB_forge.php
+++ b/system/database/DB_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Database Forge Class
@@ -34,27 +35,127 @@
  */
 abstract class CI_DB_forge {
 
+	/**
+	 * Database object
+	 *
+	 * @var	object
+	 */
+	protected $db;
+
+	/**
+	 * Fields data
+	 *
+	 * @var	array
+	 */
 	public $fields		= array();
+
+	/**
+	 * Keys data
+	 *
+	 * @var	array
+	 */
 	public $keys		= array();
+
+	/**
+	 * Primary Keys data
+	 *
+	 * @var	array
+	 */
 	public $primary_keys	= array();
+
+	/**
+	 * Database character set
+	 *
+	 * @var	string
+	 */
 	public $db_char_set	= '';
 
-	// Platform specific SQL strings
+	// --------------------------------------------------------------------
+
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_create_database	= 'CREATE DATABASE %s';
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_drop_database	= 'DROP DATABASE %s';
-	protected $_drop_table		= 'DROP TABLE IF EXISTS %s';
-	protected $_rename_table	= 'ALTER TABLE %s RENAME TO %s';
 
 	/**
-	 * Constructor
+	 * CREATE TABLE statement
 	 *
+	 * @var	string
+	 */
+	protected $_create_table	= "%s %s (%s\n)";
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= 'CREATE TABLE IF NOT EXISTS';
+
+	/**
+	 * CREATE TABLE keys flag
+	 *
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
+	 */
+	protected $_create_table_keys	= FALSE;
+
+	/**
+	 * DROP TABLE IF EXISTS statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * RENAME TABLE statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= 'ALTER TABLE %s RENAME TO %s;';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= TRUE;
+
+	/**
+	 * NULL value representatin in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= '';
+
+	/**
+	 * DEFAULT value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_default		= ' DEFAULT ';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		// Assign the main database object to $this->db
-		$CI =& get_instance();
-		$this->db =& $CI->db;
+		$this->db =& $db;
 		log_message('debug', 'Database Forge Class Initialized');
 	}
 
@@ -63,14 +164,14 @@ abstract class CI_DB_forge {
 	/**
 	 * Create database
 	 *
-	 * @param	string	the database name
+	 * @param	string	$db_name
 	 * @return	bool
 	 */
 	public function create_database($db_name)
 	{
 		if ($this->_create_database === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 		elseif ( ! $this->db->query(sprintf($this->_create_database, $db_name, $this->db->char_set, $this->db->dbcollat)))
 		{
@@ -90,7 +191,7 @@ abstract class CI_DB_forge {
 	/**
 	 * Drop database
 	 *
-	 * @param	string	the database name
+	 * @param	string	$db_name
 	 * @return	bool
 	 */
 	public function drop_database($db_name)
@@ -102,7 +203,7 @@ abstract class CI_DB_forge {
 		}
 		elseif ($this->_drop_database === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 		elseif ( ! $this->db->query(sprintf($this->_drop_database, $db_name)))
 		{
@@ -126,25 +227,25 @@ abstract class CI_DB_forge {
 	/**
 	 * Add Key
 	 *
-	 * @param	string	key
-	 * @param	string	type
+	 * @param	string	$key
+	 * @param	bool	$primary
 	 * @return	object
 	 */
 	public function add_key($key = '', $primary = FALSE)
 	{
-		if (is_array($key))
+		if (empty($key))
+		{
+			show_error('Key information is required for that operation.');
+		}
+
+		if ($primary === TRUE && is_array($key))
 		{
 			foreach ($key as $one)
 			{
 				$this->add_key($one, $primary);
 			}
 
-			return;
-		}
-
-		if ($key === '')
-		{
-			show_error('Key information is required for that operation.');
+			return $this;
 		}
 
 		if ($primary === TRUE)
@@ -164,12 +265,12 @@ abstract class CI_DB_forge {
 	/**
 	 * Add Field
 	 *
-	 * @param	string	collation
+	 * @param	array	$field
 	 * @return	object
 	 */
 	public function add_field($field = '')
 	{
-		if ($field === '')
+		if (empty($field))
 		{
 			show_error('Field information is required.');
 		}
@@ -211,8 +312,8 @@ abstract class CI_DB_forge {
 	/**
 	 * Create Table
 	 *
-	 * @param	string	$table = ''
-	 * @param	bool	$if_not_exists = FALSE
+	 * @param	string	$table		Table name
+	 * @param	bool	$if_not_exists	Whether to add IF NOT EXISTS condition
 	 * @return	bool
 	 */
 	public function create_table($table = '', $if_not_exists = FALSE)
@@ -221,51 +322,129 @@ abstract class CI_DB_forge {
 		{
 			show_error('A table name is required for that operation.');
 		}
+		else
+		{
+			$table = $this->db->dbprefix.$table;
+		}
 
 		if (count($this->fields) === 0)
 		{
 			show_error('Field information is required.');
 		}
 
-		$sql = $this->_create_table($this->db->dbprefix.$table, $this->fields, $this->primary_keys, $this->keys, $if_not_exists);
-		$this->_reset();
+		$sql = $this->_create_table($table, $if_not_exists);
 
 		if (is_bool($sql))
 		{
-			return $sql;
+			$this->_reset();
+			if ($sql === FALSE)
+			{
+				return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+			}
 		}
 
-		if (($result = $this->db->query($sql)) !== FALSE && ! empty($this->db->data_cache['table_names']))
+		if (($result = $this->db->query($sql)) !== FALSE)
 		{
-			$this->db->data_cache['table_names'][] = $this->db->dbprefix.$table;
+			empty($this->db->data_cache['table_names']) OR $this->db->data_cache['table_names'][] = $table;
+
+			// Most databases don't support creating indexes from within the CREATE TABLE statement
+			if ( ! empty($this->keys))
+			{
+				for ($i = 0, $sqls = $this->_process_indexes($table), $c = count($sqls); $i < $c; $i++)
+				{
+					$this->db->query($sqls[$i]);
+				}
+			}
 		}
 
+		$this->_reset();
 		return $result;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
+	 * Create Table
+	 *
+	 * @param	string	$table		Table name
+	 * @param	bool	$if_not_exists	Whether to add 'IF NOT EXISTS' condition
+	 * @return	mixed
+	 */
+	protected function _create_table($table, $if_not_exists)
+	{
+		if ($if_not_exists === TRUE && $this->_create_table_if === FALSE)
+		{
+			if ($this->db->table_exists($table))
+			{
+				return TRUE;
+			}
+			else
+			{
+				$if_not_exists = FALSE;
+			}
+		}
+
+		$sql = ($if_not_exists)
+			? sprintf($this->_create_table_if, $this->db->escape_identifiers($table))
+			: 'CREATE TABLE';
+
+		$columns = $this->_process_fields(TRUE);
+		for ($i = 0, $c = count($columns); $i < $c; $i++)
+		{
+			$columns[$i] = ($columns[$i]['_literal'] !== FALSE)
+					? "\n\t".$columns[$i]['_literal']
+					: "\n\t".$this->_process_column($columns[$i]);
+		}
+
+		$columns = implode(',', $columns)
+				.$this->_process_primary_keys($table);
+
+		// Are indexes created from within the CREATE TABLE statement? (e.g. in MySQL)
+		if ($this->_create_table_keys === TRUE)
+		{
+			$columns .= $this->_process_indexes();
+		}
+
+		// _create_table will usually have the following format: "%s %s (%s\n)"
+		$sql = sprintf($this->_create_table.';',
+			$sql,
+			$this->db->escape_identifiers($table),
+			$columns
+		);
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Drop Table
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table_name	Table name
+	 * @param	bool	$if_exists	Whether to add an IF EXISTS condition
 	 * @return	bool
 	 */
-	public function drop_table($table_name)
+	public function drop_table($table_name, $if_exists = FALSE)
 	{
 		if ($table_name === '')
 		{
 			return ($this->db->db_debug) ? $this->db->display_error('db_table_name_required') : FALSE;
 		}
-		elseif ($this->_drop_table === FALSE)
+
+		$query = $this->_drop_table($this->db->dbprefix.$table_name, $if_exists);
+		if ($query === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+		}
+		elseif ($query === TRUE)
+		{
+			return TRUE;
 		}
 
-		$result = $this->db->query(sprintf($this->_drop_table, $this->db->escape_identifiers($this->db->dbprefix.$table_name)));
+		$query = $this->db->query($query);
 
 		// Update table list cache
-		if ($result && ! empty($this->db->data_cache['table_names']))
+		if ($query && ! empty($this->db->data_cache['table_names']))
 		{
 			$key = array_search(strtolower($this->db->dbprefix.$table_name), array_map('strtolower', $this->db->data_cache['table_names']), TRUE);
 			if ($key !== FALSE)
@@ -274,7 +453,40 @@ abstract class CI_DB_forge {
 			}
 		}
 
-		return $result;
+		return $query;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Drop Table
+	 *
+	 * Generates a platform-specific DROP TABLE string
+	 *
+	 * @param	string	$table		Table name
+	 * @param	bool	$if_exists	Whether to add an IF EXISTS condition
+	 * @return	string
+	 */
+	protected function _drop_table($table, $if_exists)
+	{
+		$sql = 'DROP TABLE';
+
+		if ($if_exists)
+		{
+			if ($this->_drop_table_if === FALSE)
+			{
+				if ( ! $this->db->table_exists($table))
+				{
+					return TRUE;
+				}
+			}
+			else
+			{
+				$sql = sprintf($this->_drop_table_if, $this->db->escape_identifiers($table));
+			}
+		}
+
+		return $sql.' '.$this->db->escape_identifiers($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -282,8 +494,8 @@ abstract class CI_DB_forge {
 	/**
 	 * Rename Table
 	 *
-	 * @param	string	the old table name
-	 * @param	string	the new table name
+	 * @param	string	$table_name	Old table name
+	 * @param	string	$new_table_name	New table name
 	 * @return	bool
 	 */
 	public function rename_table($table_name, $new_table_name)
@@ -295,7 +507,7 @@ abstract class CI_DB_forge {
 		}
 		elseif ($this->_rename_table === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 
 		$result = $this->db->query(sprintf($this->_rename_table,
@@ -320,33 +532,46 @@ abstract class CI_DB_forge {
 	/**
 	 * Column Add
 	 *
-	 * @param	string	the table name
-	 * @param	string	the column name
-	 * @param	string	the column definition
+	 * @todo	Remove deprecated $_after option in 3.1+
+	 * @param	string	$table	Table name
+	 * @param	array	$field	Column definition
+	 * @param	string	$_after	Column for AFTER clause (deprecated)
 	 * @return	bool
 	 */
-	public function add_column($table = '', $field = array(), $after_field = '')
+	public function add_column($table = '', $field = array(), $_after = NULL)
 	{
 		if ($table === '')
 		{
 			show_error('A table name is required for that operation.');
 		}
 
-		// add field info into field array, but we can only do one at a time
-		// so we cycle through
-		foreach (array_keys($field) as $k)
+		// Work-around for literal column definitions
+		if ( ! is_array($field))
 		{
-			$this->add_field(array($k => $field[$k]));
+			$field = array($field);
+		}
 
-			if (count($this->fields) === 0)
+		foreach (array_keys($field) as $k)
+		{
+			// Backwards-compatibility work-around for MySQL/CUBRID AFTER clause (remove in 3.1+)
+			if ($_after !== NULL && is_array($field[$k]) && ! isset($field[$k]['after']))
 			{
-				show_error('Field information is required.');
+				$field[$k]['after'] = $_after;
 			}
 
-			$sql = $this->_alter_table('ADD', $this->db->dbprefix.$table, $this->fields, $after_field);
-			$this->_reset();
+			$this->add_field(array($k => $field[$k]));
+		}
+
+		$sqls = $this->_alter_table('ADD', $this->db->dbprefix.$table, $this->_process_fields());
+		$this->_reset();
+		if ($sqls === FALSE)
+		{
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+		}
 
-			if ($this->db->query($sql) === FALSE)
+		for ($i = 0, $c = count($sqls); $i < $c; $i++)
+		{
+			if ($this->db->query($sqls[$i]) === FALSE)
 			{
 				return FALSE;
 			}
@@ -360,8 +585,8 @@ abstract class CI_DB_forge {
 	/**
 	 * Column Drop
 	 *
-	 * @param	string	the table name
-	 * @param	string	the column name
+	 * @param	string	$table		Table name
+	 * @param	string	$column_name	Column name
 	 * @return	bool
 	 */
 	public function drop_column($table = '', $column_name = '')
@@ -376,7 +601,13 @@ abstract class CI_DB_forge {
 			show_error('A column name is required for that operation.');
 		}
 
-		return $this->db->query($this->_alter_table('DROP', $this->db->dbprefix.$table, $column_name));
+		$sql = $this->_alter_table('DROP', $this->db->dbprefix.$table, $column_name);
+		if ($sql === FALSE)
+		{
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+		}
+
+		return $this->db->query($sql);
 	}
 
 	// --------------------------------------------------------------------
@@ -384,8 +615,8 @@ abstract class CI_DB_forge {
 	/**
 	 * Column Modify
 	 *
-	 * @param	string	$table = ''
-	 * @param	string	$field = array()	column definition
+	 * @param	string	$table	Table name
+	 * @param	string	$field	Column definition
 	 * @return	bool
 	 */
 	public function modify_column($table = '', $field = array())
@@ -395,32 +626,363 @@ abstract class CI_DB_forge {
 			show_error('A table name is required for that operation.');
 		}
 
-		// add field info into field array, but we can only do one at a time
-		// so we cycle through
+		// Work-around for literal column definitions
+		if ( ! is_array($field))
+		{
+			$field = array($field);
+		}
+
 		foreach (array_keys($field) as $k)
 		{
-			// If no name provided, use the current name
-			if ( ! isset($field[$k]['name']))
+			$this->add_field(array($k => $field[$k]));
+		}
+
+		if (count($this->fields) === 0)
+		{
+			show_error('Field information is required.');
+		}
+
+		$sqls = $this->_alter_table('CHANGE', $this->db->dbprefix.$table, $this->fields);
+		$this->_reset();
+		if ($sqls === FALSE)
+		{
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+		}
+
+		for ($i = 0, $c = count($sqls); $i < $c; $i++)
+		{
+			if ($this->db->query($sqls[$i]) === FALSE)
 			{
-				$field[$k]['name'] = $k;
+				return FALSE;
 			}
+		}
 
-			$this->add_field(array($k => $field[$k]));
-			if (count($this->fields) === 0)
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' ';
+
+		// DROP has everything it needs now.
+		if ($alter_type === 'DROP')
+		{
+			return $sql.'DROP COLUMN '.$this->db->escape_identifiers($field);
+		}
+
+		$sqls = array();
+		for ($i = 0, $c = count($field), $sql .= $alter_type.' COLUMN '; $i < $c; $i++)
+		{
+			$sqls[] = $sql
+				.($field[$i]['_literal'] !== FALSE ? $field[$i]['_literal'] : $this->_process_column($field[$i]));
+		}
+
+		return $sqls;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process fields
+	 *
+	 * @param	bool	$create_table
+	 * @return	array
+	 */
+	protected function _process_fields($create_table = FALSE)
+	{
+		$fields = array();
+
+		foreach ($this->fields as $key => $attributes)
+		{
+			if (is_int($key) && ! is_array($attributes))
 			{
-				show_error('Field information is required.');
+				$fields[] = array('_literal' => $attributes);
+				continue;
 			}
 
-			$sql = $this->_alter_table('CHANGE', $this->db->dbprefix.$table, $this->fields);
-			$this->_reset();
+			$attributes = array_change_key_case($attributes, CASE_UPPER);
 
-			if ($this->db->query($sql) === FALSE)
+			if ($create_table === TRUE && empty($attributes['TYPE']))
 			{
-				return FALSE;
+				continue;
+			}
+
+			if (isset($attributes['TYPE']))
+			{
+				$this->_attr_type($attributes);
+				$this->_attr_unsigned($attributes, $field);
 			}
+
+			$field = array(
+					'name'			=> $key,
+					'new_name'		=> isset($attributes['NAME']) ? $attributes['NAME'] : NULL,
+					'type'			=> isset($attributes['TYPE']) ? $attributes['TYPE'] : NULL,
+					'length'		=> '',
+					'unsigned'		=> '',
+					'null'			=> '',
+					'unique'		=> '',
+					'default'		=> '',
+					'auto_increment'	=> '',
+					'_literal'		=> FALSE
+			);
+
+			$this->_attr_default($attributes, $field);
+
+			if (isset($attributes['NULL']))
+			{
+				if ($attributes['NULL'] === TRUE)
+				{
+					$field['null'] = empty($this->_null) ? '' : ' '.$this->_null;
+				}
+				elseif ($create_table === TRUE)
+				{
+					$field['null'] = ' NOT NULL';
+				}
+			}
+
+			$this->_attr_auto_increment($attributes, $field);
+			$this->_attr_unique($attributes, $field);
+
+			if (isset($attributes['TYPE']) && ! empty($attributes['CONSTRAINT']))
+			{
+				switch (strtoupper($attributes['TYPE']))
+				{
+					case 'ENUM':
+					case 'SET':
+						$attributes['CONSTRAINT'] = $this->db->escape($attributes['CONSTRAINT']);
+					default:
+						$field['length'] = is_array($attributes['CONSTRAINT'])
+								? '('.implode(',', $attributes['CONSTRAINT']).')'
+								: '('.$attributes['CONSTRAINT'].')';
+						break;
+				}
+			}
+
+			$fields[] = $field;
 		}
 
-		return TRUE;
+		return $fields;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['default']
+			.$field['null']
+			.$field['auto_increment']
+			.$field['unique'];
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		// Usually overriden by drivers
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute UNSIGNED
+	 *
+	 * Depending on the _unsigned property value:
+	 *
+	 *	- TRUE will always set $field['unsigned'] to 'UNSIGNED'
+	 *	- FALSE will always set $field['unsigned'] to ''
+	 *	- array(TYPE) will set $field['unsigned'] to 'UNSIGNED',
+	 *		if $attributes['TYPE'] is found in the array
+	 *	- array(TYPE => UTYPE) will change $field['type'],
+	 *		from TYPE to UTYPE in case of a match
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_unsigned(&$attributes, &$field)
+	{
+		if (empty($attributes['UNSIGNED']) OR $attributes['UNSIGNED'] !== TRUE)
+		{
+			return;
+		}
+
+		// Reset the attribute in order to avoid issues if we do type conversion
+		$attributes['UNSIGNED'] = FALSE;
+
+		if (is_array($this->_unsigned))
+		{
+			foreach (array_keys($this->_unsigned) as $key)
+			{
+				if (is_int($key) && strcasecmp($attributes['TYPE'], $this->_unsigned[$key]) === 0)
+				{
+					$field['unsigned'] = ' UNSIGNED';
+					return;
+				}
+				elseif (is_string($key) && strcasecmp($attributes['TYPE'], $key) === 0)
+				{
+					$field['type'] = $key;
+					return;
+				}
+			}
+
+			return;
+		}
+
+		$field['unsigned'] = ($this->_unsigned === TRUE) ? ' UNSIGNED' : '';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute DEFAULT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_default(&$attributes, &$field)
+	{
+		if ($this->_default === FALSE)
+		{
+			return;
+		}
+
+		if (array_key_exists('DEFAULT', $attributes))
+		{
+			if ($attributes['DEFAULT'] === NULL)
+			{
+				$field['default'] = empty($this->_null) ? '' : $this->_default.$this->_null;
+
+				// Override the NULL attribute if that's our default
+				$attributes['NULL'] = NULL;
+				$field['null'] = empty($this->_null) ? '' : ' '.$this->_null;
+			}
+			else
+			{
+				$field['default'] = $this->_default.$this->db->escape($attributes['DEFAULT']);
+			}
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute UNIQUE
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_unique(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
+		{
+			$field['unique'] = ' UNIQUE';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['auto_increment'] = ' AUTO_INCREMENT';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process primary keys
+	 *
+	 * @param	string	$table	Table name
+	 * @return	string
+	 */
+	protected function _process_primary_keys($table)
+	{
+		$sql = '';
+
+		for ($i = 0, $c = count($this->primary_keys); $i < $c; $i++)
+		{
+			if ( ! isset($this->fields[$this->primary_keys[$i]]))
+			{
+				unset($this->primary_keys[$i]);
+			}
+		}
+
+		if (count($this->primary_keys) > 0)
+		{
+			$sql .= ",\n\tCONSTRAINT ".$this->db->escape_identifiers('pk_'.$table)
+				.' PRIMARY KEY('.implode(', ', $this->db->escape_identifiers($this->primary_keys)).')';
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process indexes
+	 *
+	 * @param	string	$table
+	 * @return	string
+	 */
+	protected function _process_indexes($table = NULL)
+	{
+		$table = $this->db->escape_identifiers($table);
+		$sqls = array();
+
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
+		{
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sqls[] = 'CREATE INDEX '.$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ON '.$this->db->escape_identifiers($table)
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).');';
+		}
+
+		return $sqls;
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index a3585586e..364397721 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Query Builder Class
@@ -39,42 +40,213 @@
 
 abstract class CI_DB_query_builder extends CI_DB_driver {
 
+	/**
+	 * Return DELETE SQL flag
+	 *
+	 * @var	bool
+	 */
 	protected $return_delete_sql		= FALSE;
+
+	/**
+	 * Reset DELETE data flag
+	 *
+	 * @var	bool
+	 */
 	protected $reset_delete_data		= FALSE;
 
+	/**
+	 * QB SELECT data
+	 *
+	 * @var	array
+	 */
 	protected $qb_select			= array();
+
+	/**
+	 * QB DISTINCT flag
+	 *
+	 * @var	bool
+	 */
 	protected $qb_distinct			= FALSE;
+
+	/**
+	 * QB FROM data
+	 *
+	 * @var	array
+	 */
 	protected $qb_from			= array();
+
+	/**
+	 * QB JOIN data
+	 *
+	 * @var	array
+	 */
 	protected $qb_join			= array();
+
+	/**
+	 * QB WHERE data
+	 *
+	 * @var	array
+	 */
 	protected $qb_where			= array();
+
+	/**
+	 * QB GROUP BY data
+	 *
+	 * @var	array
+	 */
 	protected $qb_groupby			= array();
+
+	/**
+	 * QB HAVING data
+	 *
+	 * @var	array
+	 */
 	protected $qb_having			= array();
+
+	/**
+	 * QB keys
+	 *
+	 * @var	array
+	 */
 	protected $qb_keys			= array();
+
+	/**
+	 * QB LIMIT data
+	 *
+	 * @var	int
+	 */
 	protected $qb_limit			= FALSE;
+
+	/**
+	 * QB OFFSET data
+	 *
+	 * @var	int
+	 */
 	protected $qb_offset			= FALSE;
+
+	/**
+	 * QB ORDER BY data
+	 *
+	 * @var	array
+	 */
 	protected $qb_orderby			= array();
+
+	/**
+	 * QB data sets
+	 *
+	 * @var	array
+	 */
 	protected $qb_set			= array();
+
+	/**
+	 * QB aliased tables list
+	 *
+	 * @var	array
+	 */
 	protected $qb_aliased_tables		= array();
-	protected $qb_store_array		= array();
+
+	/**
+	 * QB WHERE group started flag
+	 *
+	 * @var	bool
+	 */
 	protected $qb_where_group_started	= FALSE;
+
+	/**
+	 * QB WHERE group count
+	 *
+	 * @var	int
+	 */
 	protected $qb_where_group_count		= 0;
 
 	// Query Builder Caching variables
+
+	/**
+	 * QB Caching flag
+	 *
+	 * @var	bool
+	 */
 	protected $qb_caching				= FALSE;
+
+	/**
+	 * QB Cache exists list
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_exists			= array();
+
+	/**
+	 * QB Cache SELECT data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_select			= array();
+
+	/**
+	 * QB Cache FROM data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_from			= array();
+
+	/**
+	 * QB Cache JOIN data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_join			= array();
+
+	/**
+	 * QB Cache WHERE data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_where			= array();
-	protected $qb_cache_like			= array();
+
+	/**
+	 * QB Cache GROUP BY data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_groupby			= array();
+
+	/**
+	 * QB Cache HAVING data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_having			= array();
+
+	/**
+	 * QB Cache ORDER BY data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_orderby			= array();
+
+	/**
+	 * QB Cache data sets
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_set				= array();
 
+	/**
+	 * QB No Escape data
+	 *
+	 * @var	array
+	 */
 	protected $qb_no_escape 			= array();
+
+	/**
+	 * QB Cache No Escape data
+	 *
+	 * @var	array
+	 */
 	protected $qb_cache_no_escape			= array();
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Select
 	 *
@@ -182,17 +354,16 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Processing Function for the following functions:
-	 *
-	 *	select_max()
-	 *	select_min()
-	 *	select_avg()
-	 *	select_sum()
+	 * SELECT [MAX|MIN|AVG|SUM]()
 	 *
+	 * @used-by	select_max()
+	 * @used-by	select_min()
+	 * @used-by	select_avg()
+	 * @used-by	select_sum()
 	 *
-	 * @param	string	$select = ''	field name
-	 * @param	string	$alias = ''
-	 * @param	string	$type = 'MAX'
+	 * @param	string	$select	Field name
+	 * @param	string	$alias
+	 * @param	string	$type
 	 * @return	object
 	 */
 	protected function _max_min_avg_sum($select = '', $alias = '', $type = 'MAX')
@@ -233,7 +404,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * Determines the alias name based on the table
 	 *
-	 * @param	string
+	 * @param	string	$item
 	 * @return	string
 	 */
 	protected function _create_alias_from_table($item)
@@ -254,7 +425,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 *
 	 * Sets a flag which tells the query string compiler to add DISTINCT
 	 *
-	 * @param	bool
+	 * @param	bool	$val
 	 * @return	object
 	 */
 	public function distinct($val = TRUE)
@@ -270,7 +441,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 *
 	 * Generates the FROM portion of the query
 	 *
-	 * @param	mixed	can be a string or array
+	 * @param	mixed	$from	can be a string or array
 	 * @return	object
 	 */
 	public function from($from)
@@ -317,7 +488,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Join
+	 * JOIN
 	 *
 	 * Generates the JOIN portion of the query
 	 *
@@ -405,10 +576,10 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where
+	 * WHERE
 	 *
-	 * Generates the WHERE portion of the query. Separates
-	 * multiple calls with AND
+	 * Generates the WHERE portion of the query.
+	 * Separates multiple calls with 'AND'.
 	 *
 	 * @param	mixed
 	 * @param	mixed
@@ -423,10 +594,10 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * OR Where
+	 * OR WHERE
 	 *
-	 * Generates the WHERE portion of the query. Separates
-	 * multiple calls with OR
+	 * Generates the WHERE portion of the query.
+	 * Separates multiple calls with 'OR'.
 	 *
 	 * @param	mixed
 	 * @param	mixed
@@ -443,13 +614,16 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * WHERE, HAVING
 	 *
-	 * Called by where(), or_where(), having(), or_having()
+	 * @used-by	where()
+	 * @used-by	or_where()
+	 * @used-by	having()
+	 * @used-by	or_having()
 	 *
-	 * @param	string	'qb_where' or 'qb_having'
-	 * @param	mixed
-	 * @param	mixed
-	 * @param	string
-	 * @param	bool
+	 * @param	string	$qb_key	'qb_where' or 'qb_having'
+	 * @param	mixed	$key
+	 * @param	mixed	$value
+	 * @param	string	$type
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	protected function _wh($qb_key, $key, $value = NULL, $type = 'AND ', $escape = NULL)
@@ -504,14 +678,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where_in
+	 * WHERE IN
 	 *
-	 * Generates a WHERE field IN('item', 'item') SQL query joined with
-	 * AND if appropriate
+	 * Generates a WHERE field IN('item', 'item') SQL query,
+	 * joined with 'AND' if appropriate.
 	 *
-	 * @param	string	$key = NULL	The field to search
-	 * @param	array	$values = NULL	The values searched on
-	 * @param	bool	$escape = NULL
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function where_in($key = NULL, $values = NULL, $escape = NULL)
@@ -522,14 +696,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Or_where_in
+	 * OR WHERE IN
 	 *
-	 * Generates a WHERE field IN('item', 'item') SQL query joined with
-	 * OR if appropriate
+	 * Generates a WHERE field IN('item', 'item') SQL query,
+	 * joined with 'OR' if appropriate.
 	 *
-	 * @param	string	$key = NULL	The field to search
-	 * @param	array	$values = NULL	The values searched on
-	 * @param	bool	$escape = NULL
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function or_where_in($key = NULL, $values = NULL, $escape = NULL)
@@ -540,14 +714,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where_not_in
+	 * WHERE NOT IN
 	 *
-	 * Generates a WHERE field NOT IN('item', 'item') SQL query joined
-	 * with AND if appropriate
+	 * Generates a WHERE field NOT IN('item', 'item') SQL query,
+	 * joined with 'AND' if appropriate.
 	 *
-	 * @param	string	$key = NULL	The field to search
-	 * @param	array	$values = NULL	The values searched on
-	 * @param	bool	$escape = NULL
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function where_not_in($key = NULL, $values = NULL, $escape = NULL)
@@ -558,14 +732,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Or_where_not_in
+	 * OR WHERE NOT IN
 	 *
-	 * Generates a WHERE field NOT IN('item', 'item') SQL query joined
-	 * with OR if appropriate
+	 * Generates a WHERE field NOT IN('item', 'item') SQL query,
+	 * joined with 'OR' if appropriate.
 	 *
-	 * @param	string	$key = NULL	The field to search
-	 * @param	array	$values = NULL	The values searched on
-	 * @param	bool	$escape = NULL
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function or_where_not_in($key = NULL, $values = NULL, $escape = NULL)
@@ -576,15 +750,18 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where_in
+	 * Internal WHERE IN
 	 *
-	 * Called by where_in(), or_where_in(), where_not_in(), or_where_not_in()
+	 * @used-by	where_in()
+	 * @used-by	or_where_in()
+	 * @used-by	where_not_in()
+	 * @used-by	or_where_not_in()
 	 *
-	 * @param	string	$key = NULL	The field to search
-	 * @param	array	$values = NULL	The values searched on
-	 * @param	bool	$not = FALSE	If the statement would be IN or NOT IN
-	 * @param	string	$type = 'AND '
-	 * @param	bool	$escape = NULL
+	 * @param	string	$key	The field to search
+	 * @param	array	$values	The values searched on
+	 * @param	bool	$not	If the statement would be IN or NOT IN
+	 * @param	string	$type
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	protected function _where_in($key = NULL, $values = NULL, $not = FALSE, $type = 'AND ', $escape = NULL)
@@ -628,15 +805,15 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Like
+	 * LIKE
 	 *
-	 * Generates a %LIKE% portion of the query. Separates
-	 * multiple calls with AND
+	 * Generates a %LIKE% portion of the query.
+	 * Separates multiple calls with 'AND'.
 	 *
-	 * @param	mixed
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function like($field, $match = '', $side = 'both', $escape = NULL)
@@ -647,15 +824,15 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Not Like
+	 * NOT LIKE
 	 *
-	 * Generates a NOT LIKE portion of the query. Separates
-	 * multiple calls with AND
+	 * Generates a NOT LIKE portion of the query.
+	 * Separates multiple calls with 'AND'.
 	 *
-	 * @param	mixed
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function not_like($field, $match = '', $side = 'both', $escape = NULL)
@@ -666,15 +843,15 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * OR Like
+	 * OR LIKE
 	 *
-	 * Generates a %LIKE% portion of the query. Separates
-	 * multiple calls with OR
+	 * Generates a %LIKE% portion of the query.
+	 * Separates multiple calls with 'OR'.
 	 *
-	 * @param	mixed
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function or_like($field, $match = '', $side = 'both', $escape = NULL)
@@ -685,15 +862,15 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * OR Not Like
+	 * OR NOT LIKE
 	 *
-	 * Generates a NOT LIKE portion of the query. Separates
-	 * multiple calls with OR
+	 * Generates a NOT LIKE portion of the query.
+	 * Separates multiple calls with 'OR'.
 	 *
-	 * @param	mixed
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$side
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function or_not_like($field, $match = '', $side = 'both', $escape = NULL)
@@ -704,16 +881,19 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Like
+	 * Internal LIKE
 	 *
-	 * Called by like(), or_like(), not_like, or_not_like()
+	 * @used-by	like()
+	 * @used-by	or_like()
+	 * @used-by	not_like()
+	 * @used-by	or_not_like()
 	 *
-	 * @param	mixed
-	 * @param	string
-	 * @param	string
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	mixed	$field
+	 * @param	string	$match
+	 * @param	string	$type
+	 * @param	string	$side
+	 * @param	string	$not
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	protected function _like($field, $match = '', $type = 'AND ', $side = 'both', $not = '', $escape = NULL)
@@ -770,8 +950,8 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * Starts a query group.
 	 *
-	 * @param	string (Internal use only)
-	 * @param	string (Internal use only)
+	 * @param	string	$not	(Internal use only)
+	 * @param	string	$type	(Internal use only)
 	 * @return	object
 	 */
 	public function group_start($not = '', $type = 'AND ')
@@ -859,9 +1039,12 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * Group_get_type
 	 *
-	 * Called by group_start(), _like(), _where() and _where_in()
+	 * @used-by	group_start()
+	 * @used-by	_like()
+	 * @used-by	_wh()
+	 * @used-by	_where_in()
 	 *
-	 * @param	string
+	 * @param	string	$type
 	 * @return	string
 	 */
 	protected function _group_get_type($type)
@@ -880,8 +1063,8 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * GROUP BY
 	 *
-	 * @param	string
-	 * @param	bool
+	 * @param	string	$by
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function group_by($by, $escape = NULL)
@@ -918,13 +1101,13 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Sets the HAVING value
+	 * HAVING
 	 *
-	 * Separates multiple calls with AND
+	 * Separates multiple calls with 'AND'.
 	 *
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	string	$key
+	 * @param	string	$value
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function having($key, $value = NULL, $escape = NULL)
@@ -935,13 +1118,13 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Sets the OR HAVING value
+	 * OR HAVING
 	 *
-	 * Separates multiple calls with OR
+	 * Separates multiple calls with 'OR'.
 	 *
-	 * @param	string
-	 * @param	string
-	 * @param	bool
+	 * @param	string	$key
+	 * @param	string	$value
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function or_having($key, $value = NULL, $escape = NULL)
@@ -952,11 +1135,11 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Sets the ORDER BY value
+	 * ORDER BY
 	 *
-	 * @param	string
-	 * @param	string	direction: ASC or DESC
-	 * @param	bool	enable field name escaping
+	 * @param	string	$orderby
+	 * @param	string	$direction	ASC or DESC
+	 * @param	bool	$escape
 	 * @return	object
 	 */
 	public function order_by($orderby, $direction = '', $escape = NULL)
@@ -1008,10 +1191,10 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Sets the LIMIT value
+	 * LIMIT
 	 *
-	 * @param	int	the limit value
-	 * @param	int	the offset value
+	 * @param	int	$value	LIMIT value
+	 * @param	int	$offset	OFFSET value
 	 * @return	object
 	 */
 	public function limit($value, $offset = FALSE)
@@ -1027,7 +1210,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	/**
 	 * Sets the OFFSET value
 	 *
-	 * @param	int	the offset value
+	 * @param	int	$offset	OFFSET value
 	 * @return	object
 	 */
 	public function offset($offset)
@@ -1039,11 +1222,11 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT string
 	 *
-	 * Generates a platform-specific LIMIT clause
+	 * Generates a platform-specific LIMIT clause.
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
@@ -1183,10 +1366,10 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 *
 	 * Allows the where clause, limit and offset to be added directly
 	 *
-	 * @param	string	$table = ''
-	 * @param	string	$where = NULL
-	 * @param	int	$limit = NULL
-	 * @param	int	$offset = NULL
+	 * @param	string	$table
+	 * @param	string	$where
+	 * @param	int	$limit
+	 * @param	int	$offset
 	 * @return	object
 	 */
 	public function get_where($table = '', $where = NULL, $limit = NULL, $offset = NULL)
@@ -1218,15 +1401,16 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 *
 	 * Compiles batch insert strings and runs the queries
 	 *
-	 * @param	string	$table = ''	table to insert into
-	 * @param	array	$set 		an associative array of insert values
-	 * @return	int	number of rows inserted or FALSE on failure
+	 * @param	string	$table	Table to insert into
+	 * @param	array	$set 	An associative array of insert values
+	 * @param	bool	$escape	Whether to escape values and identifiers
+	 * @return	int	Number of rows inserted or FALSE on failure
 	 */
-	public function insert_batch($table = '', $set = NULL)
+	public function insert_batch($table = '', $set = NULL, $escape = NULL)
 	{
 		if ( ! is_null($set))
 		{
-			$this->set_insert_batch($set);
+			$this->set_insert_batch($set, '', $escape);
 		}
 
 		if (count($this->qb_set) === 0)
@@ -1249,7 +1433,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		$affected_rows = 0;
 		for ($i = 0, $total = count($this->qb_set); $i < $total; $i += 100)
 		{
-			$this->query($this->_insert_batch($this->protect_identifiers($table, TRUE, NULL, FALSE), $this->qb_keys, array_slice($this->qb_set, $i, 100)));
+			$this->query($this->_insert_batch($this->protect_identifiers($table, TRUE, $escape, FALSE), $this->qb_keys, array_slice($this->qb_set, $i, 100)));
 			$affected_rows += $this->affected_rows();
 		}
 
@@ -1260,13 +1444,13 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert_batch statement
+	 * Insert batch statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data.
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return	string
 	 */
 	protected function _insert_batch($table, $keys, $values)
@@ -1375,13 +1559,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 *
 	 * @param	string	the table to insert data into
 	 * @param	array	an associative array of insert values
+	 * @param	bool	$escape	Whether to escape values and identifiers
 	 * @return	object
 	 */
-	public function insert($table = '', $set = NULL)
+	public function insert($table = '', $set = NULL, $escape = NULL)
 	{
 		if ( ! is_null($set))
 		{
-			$this->set($set);
+			$this->set($set, '', $escape);
 		}
 
 		if ($this->_validate_insert($table) === FALSE)
@@ -1391,7 +1576,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 
 		$sql = $this->_insert(
 			$this->protect_identifiers(
-				$this->qb_from[0], TRUE, NULL, FALSE
+				$this->qb_from[0], TRUE, $escape, FALSE
 			),
 			array_keys($this->qb_set),
 			array_values($this->qb_set)
@@ -1539,14 +1724,14 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Update
+	 * UPDATE
 	 *
-	 * Compiles an update string and runs the query
+	 * Compiles an update string and runs the query.
 	 *
-	 * @param	string	$table = ''
-	 * @param	array	$set = NULL	an associative array of update values
-	 * @param	mixed	$where = NULL
-	 * @param	int	$limit = NULL
+	 * @param	string	$table
+	 * @param	array	$set	An associative array of update values
+	 * @param	mixed	$where
+	 * @param	int	$limit
 	 * @return	object
 	 */
 	public function update($table = '', $set = NULL, $where = NULL, $limit = NULL)
@@ -1575,7 +1760,6 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		}
 
 		$sql = $this->_update($this->protect_identifiers($this->qb_from[0], TRUE, NULL, FALSE), $this->qb_set);
-
 		$this->_reset_write();
 		return $this->query($sql);
 	}
@@ -1980,7 +2164,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 * Generates a query string based on which functions were used.
 	 * Should not be called directly.
 	 *
-	 * @param	bool	$select_override = FALSE
+	 * @param	bool	$select_override
 	 * @return	string
 	 */
 	protected function _compile_select($select_override = FALSE)
@@ -2053,7 +2237,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 * where(), or_where(), having(), or_having are called prior to from(),
 	 * join() and dbprefix is added only if needed.
 	 *
-	 * @param	string	'qb_where' or 'qb_having'
+	 * @param	string	$qb_key	'qb_where' or 'qb_having'
 	 * @return	string	SQL statement
 	 */
 	protected function _compile_wh($qb_key)
@@ -2291,7 +2475,6 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 			'qb_cache_from'			=> array(),
 			'qb_cache_join'			=> array(),
 			'qb_cache_where'		=> array(),
-			'qb_cache_like'			=> array(),
 			'qb_cache_groupby'		=> array(),
 			'qb_cache_having'		=> array(),
 			'qb_cache_orderby'		=> array(),
@@ -2398,10 +2581,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	{
 		foreach ($qb_reset_items as $item => $default_value)
 		{
-			if ( ! in_array($item, $this->qb_store_array))
-			{
-				$this->$item = $default_value;
-			}
+			$this->$item = $default_value;
 		}
 	}
 
diff --git a/system/database/DB_result.php b/system/database/DB_result.php
index 76093f918..9d19075ba 100644
--- a/system/database/DB_result.php
+++ b/system/database/DB_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Database Result Class
@@ -38,19 +39,68 @@
  */
 class CI_DB_result {
 
+	/**
+	 * Connection ID
+	 *
+	 * @var	resource|object
+	 */
 	public $conn_id;
+
+	/**
+	 * Result ID
+	 *
+	 * @var	resource|object
+	 */
 	public $result_id;
+
+	/**
+	 * Result Array
+	 *
+	 * @var	array[]
+	 */
 	public $result_array			= array();
+
+	/**
+	 * Result Object
+	 *
+	 * @var	object[]
+	 */
 	public $result_object			= array();
+
+	/**
+	 * Custom Result Object
+	 *
+	 * @var	object[]
+	 */
 	public $custom_result_object		= array();
+
+	/**
+	 * Current Row index
+	 *
+	 * @var	int
+	 */
 	public $current_row			= 0;
+
+	/**
+	 * Number of rows
+	 *
+	 * @var	int
+	 */
 	public $num_rows;
+
+	/**
+	 * Row data
+	 *
+	 * @var	array
+	 */
 	public $row_data;
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Constructor
 	 *
-	 * @param	object
+	 * @param	object	$driver_object
 	 * @return	void
 	 */
 	public function __construct(&$driver_object)
@@ -89,7 +139,7 @@ class CI_DB_result {
 	/**
 	 * Query result. Acts as a wrapper function for the following functions.
 	 *
-	 * @param	string	'object', 'array' or a custom class name
+	 * @param	string	$type	'object', 'array' or a custom class name
 	 * @return	array
 	 */
 	public function result($type = 'object')
@@ -113,8 +163,8 @@ class CI_DB_result {
 	/**
 	 * Custom query result.
 	 *
-	 * @param	string	A string that represents the type of object you want back
-	 * @return	array	of objects
+	 * @param	string	$class_name
+	 * @return	array
 	 */
 	public function custom_result_object($class_name)
 	{
@@ -249,10 +299,12 @@ class CI_DB_result {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Query result.  Acts as a wrapper function for the following functions.
+	 * Row
+	 *
+	 * A wrapper method.
 	 *
-	 * @param	mixed	$n = 0
-	 * @param	string	$type = 'object'	'object' or 'array'
+	 * @param	mixed	$n
+	 * @param	string	$type	'object' or 'array'
 	 * @return	mixed
 	 */
 	public function row($n = 0, $type = 'object')
@@ -339,7 +391,7 @@ class CI_DB_result {
 	/**
 	 * Returns a single result row - object version
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	object
 	 */
 	public function row_object($n = 0)
@@ -363,7 +415,7 @@ class CI_DB_result {
 	/**
 	 * Returns a single result row - array version
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	array
 	 */
 	public function row_array($n = 0)
@@ -387,7 +439,7 @@ class CI_DB_result {
 	/**
 	 * Returns the "first" row
 	 *
-	 * @param	string	$type = 'object'
+	 * @param	string	$type
 	 * @return	mixed
 	 */
 	public function first_row($type = 'object')
@@ -401,7 +453,7 @@ class CI_DB_result {
 	/**
 	 * Returns the "last" row
 	 *
-	 * @param	string	$type = 'object'
+	 * @param	string	$type
 	 * @return	mixed
 	 */
 	public function last_row($type = 'object')
@@ -415,7 +467,7 @@ class CI_DB_result {
 	/**
 	 * Returns the "next" row
 	 *
-	 * @param	string	$type = 'object'
+	 * @param	string	$type
 	 * @return	mixed
 	 */
 	public function next_row($type = 'object')
@@ -439,7 +491,7 @@ class CI_DB_result {
 	/**
 	 * Returns the "previous" row
 	 *
-	 * @param	string	$type = 'object'
+	 * @param	string	$type
 	 * @return	mixed
 	 */
 	public function previous_row($type = 'object')
@@ -462,7 +514,7 @@ class CI_DB_result {
 	/**
 	 * Returns an unbuffered row and move pointer to next row
 	 *
-	 * @param	string	$type = 'object'	'array', 'object' or a custom class name
+	 * @param	string	$type	'array', 'object' or a custom class name
 	 * @return	mixed
 	 */
 	public function unbuffered_row($type = 'object')
@@ -482,7 +534,7 @@ class CI_DB_result {
 	// --------------------------------------------------------------------
 
 	/**
-	 * The following functions are normally overloaded by the identically named
+	 * The following methods are normally overloaded by the identically named
 	 * methods in the platform-specific driver -- except when query caching
 	 * is used. When caching is enabled we do not load the other driver.
 	 * These functions are primarily here to prevent undefined function errors
@@ -490,13 +542,118 @@ class CI_DB_result {
 	 * operational due to the unavailability of the database resource IDs with
 	 * cached results.
 	 */
-	public function num_fields() { return 0; }
-	public function list_fields() { return array(); }
-	public function field_data() { return array(); }
-	public function free_result() { $this->result_id = FALSE; }
-	protected function _data_seek() { return FALSE; }
-	protected function _fetch_assoc() { return array(); }
-	protected function _fetch_object() { return array(); }
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Number of fields in the result set
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @return	int
+	 */
+	public function num_fields()
+	{
+		return 0;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Fetch Field Names
+	 *
+	 * Generates an array of column names.
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @return	array
+	 */
+	public function list_fields()
+	{
+		return array();
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field data
+	 *
+	 * Generates an array of objects containing field meta-data.
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @return	array
+	 */
+	public function field_data()
+	{
+		return array();
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Free the result
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @return	void
+	 */
+	public function free_result()
+	{
+		$this->result_id = FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Data Seek
+	 *
+	 * Moves the internal pointer to the desired offset. We call
+	 * this internally before fetching results to make sure the
+	 * result set starts at zero.
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @param	int	$n
+	 * @return	bool
+	 */
+	protected function _data_seek($n = 0)
+	{
+		return FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Result - associative array
+	 *
+	 * Returns the result set as an array.
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @return	array
+	 */
+	protected function _fetch_assoc()
+	{
+		return array();
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Result - object
+	 *
+	 * Returns the result set as an object.
+	 *
+	 * Overriden by driver result classes.
+	 *
+	 * @param	string	$class_name
+	 * @return	object
+	 */
+	protected function _fetch_object($class_name = 'stdClass')
+	{
+		return array();
+	}
 
 }
 
diff --git a/system/database/DB_utility.php b/system/database/DB_utility.php
index 8078e2bf6..488ebf3ac 100644
--- a/system/database/DB_utility.php
+++ b/system/database/DB_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Database Utility Class
@@ -32,25 +33,49 @@
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/database/
  */
-abstract class CI_DB_utility extends CI_DB_forge {
+abstract class CI_DB_utility {
 
-	public $db;
+	/**
+	 * Database object
+	 *
+	 * @var	object
+	 */
+	protected $db;
+
+	// --------------------------------------------------------------------
 
-	// Platform specific SQL strings
-	// Just setting those defaults to FALSE as they are mostly MySQL-specific
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
+	protected $_list_databases		= FALSE;
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= FALSE;
+
+	/**
+	 * REPAIR TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_repair_table	= FALSE;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
+	 * @param	object	&$db	Database object
 	 * @return	void
 	 */
-	public function __construct()
+	public function __construct(&$db)
 	{
-		// Assign the main database object to $this->db
-		$CI =& get_instance();
-		$this->db =& $CI->db;
+		$this->db =& $db;
 		log_message('debug', 'Database Utility Class Initialized');
 	}
 
@@ -70,7 +95,7 @@ abstract class CI_DB_utility extends CI_DB_forge {
 		}
 		elseif ($this->_list_databases === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 
 		$this->db->data_cache['db_names'] = array();
@@ -94,7 +119,7 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Determine if a particular database exists
 	 *
-	 * @param	string
+	 * @param	string	$database_name
 	 * @return	bool
 	 */
 	public function database_exists($database_name)
@@ -107,14 +132,14 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Optimize Table
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table_name
 	 * @return	mixed
 	 */
 	public function optimize_table($table_name)
 	{
 		if ($this->_optimize_table === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 
 		$query = $this->db->query(sprintf($this->_optimize_table, $this->db->escape_identifiers($table_name)));
@@ -138,7 +163,7 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	{
 		if ($this->_optimize_table === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 
 		$result = array();
@@ -168,14 +193,14 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Repair Table
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table_name
 	 * @return	mixed
 	 */
 	public function repair_table($table_name)
 	{
 		if ($this->_repair_table === FALSE)
 		{
-			return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+			return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 		}
 
 		$query = $this->db->query(sprintf($this->_repair_table, $this->db->escape_identifiers($table_name)));
@@ -193,10 +218,10 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Generate CSV from a query result object
 	 *
-	 * @param	object	The query result object
-	 * @param	string	The delimiter - comma by default
-	 * @param	string	The newline character - \n by default
-	 * @param	string	The enclosure - double quote by default
+	 * @param	object	$query		Query result object
+	 * @param	string	$delim		Delimiter (default: ,)
+	 * @param	string	$newline	Newline character (default: \n)
+	 * @param	string	$enclosure	Enclosure (default: ")
 	 * @return	string
 	 */
 	public function csv_from_result($query, $delim = ',', $newline = "\n", $enclosure = '"')
@@ -233,8 +258,8 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Generate XML data from a query result object
 	 *
-	 * @param	object	The query result object
-	 * @param	array	Any preferences
+	 * @param	object	$query	Query result object
+	 * @param	array	$params	Any preferences
 	 * @return	string
 	 */
 	public function xml_from_result($query, $params = array())
@@ -280,7 +305,7 @@ abstract class CI_DB_utility extends CI_DB_forge {
 	/**
 	 * Database Backup
 	 *
-	 * @param	array	$params = array()
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function backup($params = array())
@@ -293,8 +318,6 @@ abstract class CI_DB_utility extends CI_DB_forge {
 			$params = array('tables' => $params);
 		}
 
-		// ------------------------------------------------------
-
 		// Set up our default preferences
 		$prefs = array(
 				'tables'		=> array(),
@@ -338,7 +361,7 @@ abstract class CI_DB_utility extends CI_DB_forge {
 		{
 			if ($this->db->db_debug)
 			{
-				return $this->db->display_error('db_unsuported_compression');
+				return $this->db->display_error('db_unsupported_compression');
 			}
 
 			$prefs['format'] = 'txt';
diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index 8e77d8396..c89a924d3 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * CUBRID Database Adapter Class
@@ -40,18 +41,33 @@
  */
 class CI_DB_cubrid_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'cubrid';
 
-	// The character used for escaping - no need in CUBRID
-	protected $_escape_char = '`';
+	/**
+	 * Auto-commit flag
+	 *
+	 * @var	bool
+	 */
+	public $auto_commit = TRUE;
 
-	protected $_random_keyword = ' RAND()'; // database specific random keyword
+	// --------------------------------------------------------------------
 
-	// CUBRID-specific properties
-	public $auto_commit = TRUE;
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
+	protected $_escape_char = '`';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * @param	array	$params
 	 * @return	void
@@ -113,7 +129,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 * Except for determining if a persistent connection should be used,
 	 * the rest of the logic is the same for db_connect() and db_pconnect().
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	resource
 	 */
 	protected function _cubrid_connect($persistent = FALSE)
@@ -163,9 +179,18 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 */
 	public function version()
 	{
-		return isset($this->data_cache['version'])
-			? $this->data_cache['version']
-			: $this->data_cache['version'] = cubrid_get_server_info($this->conn_id);
+		if (isset($this->data_cache['version']))
+		{
+			return $this->data_cache['version'];
+		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
+
+		return ( ! $this->conn_id OR ($version = cubrid_get_server_info($this->conn_id)) === FALSE)
+			? FALSE
+			: $this->data_cache['version'] = $version;
 	}
 
 	// --------------------------------------------------------------------
@@ -173,7 +198,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -186,7 +211,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -265,8 +290,8 @@ class CI_DB_cubrid_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -332,7 +357,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -354,7 +379,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -369,7 +394,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -399,9 +424,9 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
diff --git a/system/database/drivers/cubrid/cubrid_forge.php b/system/database/drivers/cubrid/cubrid_forge.php
index d328aa241..05762ba5a 100644
--- a/system/database/drivers/cubrid/cubrid_forge.php
+++ b/system/database/drivers/cubrid/cubrid_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * CUBRID Forge Class
@@ -34,181 +35,175 @@
  */
 class CI_DB_cubrid_forge extends CI_DB_forge {
 
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_create_database	= FALSE;
+
+	/**
+	 * CREATE TABLE keys flag
+	 *
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
+	 */
+	protected $_create_table_keys	= TRUE;
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_drop_database	= FALSE;
 
 	/**
-	 * Process Fields
+	 * CREATE TABLE IF statement
 	 *
-	 * @param	mixed	the fields
-	 * @return	string
+	 * @var	string
+	 */
+	protected $_create_table_if	= FALSE;
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SHORT'		=> 'INTEGER',
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT',
+		'BIGINT'	=> 'NUMERIC',
+		'FLOAT'		=> 'DOUBLE',
+		'REAL'		=> 'DOUBLE'
+	);
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _process_fields($fields)
+	protected function _alter_table($alter_type, $table, $field)
 	{
-		$current_field_count = 0;
-		$sql = '';
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
 
-		foreach ($fields as $field => $attributes)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
+			if ($field[$i]['_literal'] !== FALSE)
 			{
-				$sql .= "\n\t".$attributes;
+				$sqls[] = $sql.' CHANGE '.$field[$i]['_literal'];
 			}
 			else
 			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field);
-
-				empty($attributes['NAME']) OR $sql .= ' '.$this->db->escape_identifiers($attributes['NAME']).' ';
-
-				if ( ! empty($attributes['TYPE']))
-				{
-					$sql .= ' '.$attributes['TYPE'];
-
-					if ( ! empty($attributes['CONSTRAINT']))
-					{
-						switch (strtolower($attributes['TYPE']))
-						{
-							case 'decimal':
-							case 'float':
-							case 'numeric':
-								$sql .= '('.implode(',', $attributes['CONSTRAINT']).')';
-								break;
-							case 'enum':
-								// Will be supported in the future as part a part of
-								// MySQL compatibility features.
-								break;
-							case 'set':
-								$sql .= '("'.implode('","', $attributes['CONSTRAINT']).'")';
-								break;
-							default:
-								$sql .= '('.$attributes['CONSTRAINT'].')';
-						}
-					}
-				}
-
-			/* As of version 8.4.1 CUBRID does not support UNSIGNED INTEGER data type.
-			 * Will be supported in the next release as a part of MySQL Compatibility.
-			 *
-				if (isset($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-			 */
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
-
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
+				$sqls[] = $sql.' CHANGE '.$this->_process_column($field[$i]);
+				if ( ! empty($field[$i]['new_name']))
 				{
-					$sql .= ' AUTO_INCREMENT';
+					$sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
+						.' AS '.$this->db->escape_identifiers($field[$i]['name']);
 				}
-
-				if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
-				{
-					$sql .= ' UNIQUE';
-				}
-			}
-
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
 			}
 		}
 
-		return $sql;
+		return $sqls;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * Process column
 	 *
-	 * @param	string	the table name
-	 * @param	mixed	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @param	array	$field
+	 * @return	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _process_column($field)
 	{
-		$sql = 'CREATE TABLE ';
+		$extra_clause = isset($field['after'])
+			? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';
 
-		/* As of version 8.4.1 CUBRID does not support this SQL syntax.
-		if ($if_not_exists === TRUE)
+		if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
 		{
-			$sql .= 'IF NOT EXISTS ';
+			$extra_clause = ' FIRST';
 		}
-		*/
 
-		$sql .= $this->db->escape_identifiers($table).' ('.$this->_process_fields($fields);
+		return $this->db->escape_identifiers($field['name'])
+			.(empty($field['new_name']) ? '' : $this->db->escape_identifiers($field['new_name']))
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['null']
+			.$field['default']
+			.$field['auto_increment']
+			.$field['unique']
+			.$extra_clause;
+	}
 
-		// If there is a PK defined
-		if (count($primary_keys) > 0)
-		{
-			$key_name = $this->db->escape_identifiers('pk_'.$table.'_'.implode('_', $primary_keys));
-			$sql .= ",\n\tCONSTRAINT ".$key_name.' PRIMARY KEY('.implode(', ', $this->db->escape_identifiers($primary_keys)).')';
-		}
+	// --------------------------------------------------------------------
 
-		if (is_array($keys) && count($keys) > 0)
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
 		{
-			foreach ($keys as $key)
-			{
-				if (is_array($key))
-				{
-					$key_name = $this->db->escape_identifiers('idx_'.$table.implode('_', $key));
-					$key = $this->db->escape_identifiers($key);
-				}
-				else
-				{
-					$key_name = $this->db->escape_identifiers('idx_'.$table.$key);
-					$key = array($key_name);
-				}
-
-				$sql .= ",\n\tKEY ".$key_name.' ('.implode(', ', $key).')';
-			}
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			default: return;
 		}
-
-		return $sql."\n);";
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
-	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Process indexes
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	array	fields
-	 * @param	string	the field after which we should add the new field
+	 * @param	string	$table	(ignored)
 	 * @return	string
 	 */
-	protected function _alter_table($alter_type, $table, $fields, $after_field = '')
+	protected function _process_indexes($table = NULL)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' ';
+		$sql = '';
 
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
 		{
-			return $sql.$this->db->escape_identifiers($fields);
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
 		}
 
-		return $sql.$this->_process_fields($fields)
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+		$this->keys = array();
+
+		return $sql;
 	}
 
 }
diff --git a/system/database/drivers/cubrid/cubrid_result.php b/system/database/drivers/cubrid/cubrid_result.php
index 360c50dc2..30aed38d9 100644
--- a/system/database/drivers/cubrid/cubrid_result.php
+++ b/system/database/drivers/cubrid/cubrid_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * CUBRID Result Class
@@ -130,9 +131,9 @@ class CI_DB_cubrid_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -161,7 +162,7 @@ class CI_DB_cubrid_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/cubrid/cubrid_utility.php b/system/database/drivers/cubrid/cubrid_utility.php
index ea8feb4e2..d76eca432 100644
--- a/system/database/drivers/cubrid/cubrid_utility.php
+++ b/system/database/drivers/cubrid/cubrid_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * CUBRID Utility Class
@@ -62,7 +63,7 @@ class CI_DB_cubrid_utility extends CI_DB_utility {
 		// No SQL based support in CUBRID as of version 8.4.0. Database or
 		// table backup can be performed using CUBRID Manager
 		// database administration tool.
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 }
 
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index c3be519bf..fc1c28f31 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Firebird/Interbase Database Adapter Class
@@ -40,15 +41,30 @@
  */
 class CI_DB_ibase_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'ibase';
 
-	// The character used to escape with
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' Random()';
 
-	protected $_random_keyword = ' Random()'; // database specific random keyword
+	/**
+	 * IBase Transaction status flag
+	 *
+	 * @var	resource
+	 */
+	protected $_ibase_trans;
 
-	// Keeps track of the resource for the current transaction
-	protected $trans;
+	// --------------------------------------------------------------------
 
 	/**
 	 * Non-persistent database connection
@@ -103,7 +119,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -116,7 +132,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -132,7 +148,7 @@ class CI_DB_ibase_driver extends CI_DB {
 		// even if the queries produce a successful result.
 		$this->_trans_failure = ($test_mode === TRUE);
 
-		$this->trans = @ibase_trans($this->conn_id);
+		$this->_ibase_trans = @ibase_trans($this->conn_id);
 
 		return TRUE;
 	}
@@ -152,7 +168,7 @@ class CI_DB_ibase_driver extends CI_DB {
 			return TRUE;
 		}
 
-		return @ibase_commit($this->trans);
+		return @ibase_commit($this->_ibase_trans);
 	}
 
 	// --------------------------------------------------------------------
@@ -170,7 +186,7 @@ class CI_DB_ibase_driver extends CI_DB {
 			return TRUE;
 		}
 
-		return @ibase_rollback($this->trans);
+		return @ibase_rollback($this->_ibase_trans);
 	}
 
 	// --------------------------------------------------------------------
@@ -178,8 +194,8 @@ class CI_DB_ibase_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -239,7 +255,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -262,7 +278,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -277,7 +293,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -310,8 +326,8 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -327,10 +343,10 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -345,7 +361,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -357,11 +373,11 @@ class CI_DB_ibase_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/ibase/ibase_forge.php b/system/database/drivers/ibase/ibase_forge.php
index da75eb9c3..a0c4e6563 100644
--- a/system/database/drivers/ibase/ibase_forge.php
+++ b/system/database/drivers/ibase/ibase_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Interbase/Firebird Forge Class
@@ -34,12 +35,51 @@
  */
 class CI_DB_ibase_forge extends CI_DB_forge {
 
-	protected $_drop_table	= 'DROP TABLE %s';
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= FALSE;
+
+	/**
+	 * RENAME TABLE statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= FALSE;
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= FALSE;
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SMALLINT'	=> 'INTEGER',
+		'INTEGER'	=> 'INT64',
+		'FLOAT'		=> 'DOUBLE PRECISION'
+	);
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
 
 	/**
 	 * Create database
 	 *
-	 * @param	string	the database name
+	 * @param	string	$db_name
 	 * @return	string
 	 */
 	public function create_database($db_name)
@@ -57,8 +97,7 @@ class CI_DB_ibase_forge extends CI_DB_forge {
 	/**
 	 * Drop database
 	 *
-	 * @param	string	the database name
-	 *		- not used in this driver, the current db is dropped
+	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
 	public function drop_database($db_name = '')
@@ -82,110 +121,119 @@ class CI_DB_ibase_forge extends CI_DB_forge {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * ALTER TABLE
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	string
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = 'CREATE TABLE ';
-
-		$sql .= $this->db->escape_identifiers($table).'(';
-		$current_field_count = 0;
+	protected function _alter_table($alter_type, $table, $field)
+ 	{
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
 
-		foreach ($fields as $field => $attributes)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field), $sql .= $alter_type.' '; $i < $c; $i++)
 		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
+			if ($field[$i]['_literal'] !== FALSE)
 			{
-				$sql .= "\n\t".$attributes;
+				return FALSE;
 			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				empty($attributes['CONSTRAINT']) OR $sql .= '('.$attributes['CONSTRAINT'].')';
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
 
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
-
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
+			if (isset($field[$i]['type']))
+			{
+				$sqls[] = $sql.' TYPE '.$field[$i]['type'].$field[$i]['length'];
 			}
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
+			if ( ! empty($field[$i]['default']))
 			{
-				$sql .= ',';
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' SET '.$field[$i]['default'];
 			}
-		}
 
-		if (count($primary_keys) > 0)
-		{
-			$primary_keys = $this->db->escape_identifiers($primary_keys);
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $primary_keys).')';
-		}
-
-		if (is_array($keys) && count($keys) > 0)
-		{
-			foreach ($keys as $key)
+			if (isset($field[$i]['null']))
 			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
+				$sqls[] = 'UPDATE "RDB$RELATION_FIELDS" SET "RDB$NULL_FLAG" = '
+					.($field[$i]['null'] === TRUE ? 'NULL' : '1')
+					.' WHERE "RDB$FIELD_NAME" = '.$this->db->escape($field[$i]['name'])
+					.' AND "RDB$RELATION_NAME" = '.$this->db->escape($table);
+			}
 
-				$sql .= ",\n\tUNIQUE (".implode(', ', $key).')';
+			if ( ! empty($field[$i]['new_name']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' TO '.$this->db->escape_identifiers($field[$i]['new_name']);
 			}
 		}
 
-		return $sql."\n)";
+		return $sqls;
+ 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type'].$field['length']
+			.$field['null']
+			.$field['unique']
+			.$field['default'];
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute TYPE
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Performs a data type mapping between different databases.
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INT':
+				$attributes['TYPE'] = 'INTEGER';
+				return;
+			case 'BIGINT':
+				$attributes['TYPE'] = 'INT64';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_auto_increment(&$attributes, &$field)
 	{
-		return 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name)
-			.' '.$column_definition
-			.($default_value !== '' ? ' DEFAULT "'.$default_value.'"' : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+		// Not supported
 	}
 
 }
diff --git a/system/database/drivers/ibase/ibase_result.php b/system/database/drivers/ibase/ibase_result.php
index 95e55710b..bbad9d895 100644
--- a/system/database/drivers/ibase/ibase_result.php
+++ b/system/database/drivers/ibase/ibase_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Interbase/Firebird Result Class
@@ -128,7 +129,7 @@ class CI_DB_ibase_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/ibase/ibase_utility.php b/system/database/drivers/ibase/ibase_utility.php
index d0e84a7b2..5eb209ae1 100644
--- a/system/database/drivers/ibase/ibase_utility.php
+++ b/system/database/drivers/ibase/ibase_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Interbase/Firebird Utility Class
@@ -34,10 +35,8 @@
  */
 class CI_DB_ibase_utility extends CI_DB_utility {
 
-	protected $_list_databases	= FALSE;
-
 	/**
-	 * Interbase/Firebird Export
+	 * Export
 	 *
 	 * @param	string	$filename
 	 * @return	mixed
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 2063dad90..a9d53fb57 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MS SQL Database Adapter Class
@@ -40,18 +41,36 @@
  */
 class CI_DB_mssql_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'mssql';
 
-	// The character used for escaping
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
 
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
-	// MSSQL-specific properties
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier = TRUE;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Appends the port number to the hostname, if needed.
 	 *
@@ -73,7 +92,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Non-persistent database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	resource
 	 */
 	public function db_connect($persistent = FALSE)
@@ -113,7 +132,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Select the database
 	 *
-	 * @param	string	database name
+	 * @param	string	$database
 	 * @return	bool
 	 */
 	public function db_select($database = '')
@@ -139,7 +158,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	mixed	resource if rows are returned, bool otherwise
 	 */
 	protected function _execute($sql)
@@ -152,7 +171,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -212,8 +231,8 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -295,7 +314,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -320,7 +339,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -335,7 +354,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -367,8 +386,8 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -385,10 +404,10 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -403,7 +422,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -419,11 +438,11 @@ class CI_DB_mssql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
@@ -470,6 +489,29 @@ class CI_DB_mssql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * Insert batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string|bool
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		// Multiple-value inserts are only supported as of SQL Server 2008
+		if (version_compare($this->version(), '10', '>='))
+		{
+			return parent::_insert_batch($table, $keys, $values);
+		}
+
+		return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/mssql/mssql_forge.php b/system/database/drivers/mssql/mssql_forge.php
index 3a3528f7b..5eebedbf7 100644
--- a/system/database/drivers/mssql/mssql_forge.php
+++ b/system/database/drivers/mssql/mssql_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MS SQL Forge Class
@@ -34,124 +35,99 @@
  */
 class CI_DB_mssql_forge extends CI_DB_forge {
 
-	protected $_drop_table	= 'DROP TABLE %s';
-
 	/**
-	 * Create Table
+	 * CREATE TABLE IF statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	string
+	 * @var	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = ($if_not_exists === TRUE)
-			? "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'".$table."') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\n"
-			: '';
-
-		$sql .= 'CREATE TABLE '.$this->db->escape_identifiers($table).' (';
-
-		$current_field_count = 0;
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				if (stripos($attributes['TYPE'], 'INT') === FALSE && ! empty($attributes['CONSTRAINT']))
-				{
-					$sql .= '('.$attributes['CONSTRAINT'].')';
-				}
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
+	protected $_create_table_if	= "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";
 
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT'	=> 'SMALLINT',
+		'SMALLINT'	=> 'INT',
+		'INT'		=> 'BIGINT',
+		'REAL'		=> 'FLOAT'
+	);
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	// --------------------------------------------------------------------
 
-		if (count($primary_keys) > 0)
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('ADD', 'DROP'), TRUE))
 		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
+			return parent::_alter_table($alter_type, $table, $field);
 		}
 
-		if (is_array($keys) && count($keys) > 0)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' ALTER COLUMN ';
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';
-			}
+			$sqls[] = $sql.$this->_process_column($field[$i]);
 		}
 
-		return $sql."\n)";
+		return $sqls;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute TYPE
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Performs a data type mapping between different databases.
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_type(&$attributes)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name);
-
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
+		switch (strtoupper($attributes['TYPE']))
 		{
-			return $sql;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INTEGER':
+				$attributes['TYPE'] = 'INT';
+				return;
+			default: return;
 		}
+	}
 
-		return $sql.' '.$column_definition
-			.($default_value != '' ? ' DEFAULT "'.$default_value.'"' : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field != '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['auto_increment'] = ' IDENTITY(1,1)';
+		}
 	}
 
 }
diff --git a/system/database/drivers/mssql/mssql_result.php b/system/database/drivers/mssql/mssql_result.php
index 84d2814f1..c74c70abf 100644
--- a/system/database/drivers/mssql/mssql_result.php
+++ b/system/database/drivers/mssql/mssql_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MSSQL Result Class
@@ -131,9 +132,9 @@ class CI_DB_mssql_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -162,7 +163,7 @@ class CI_DB_mssql_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/mssql/mssql_utility.php b/system/database/drivers/mssql/mssql_utility.php
index 69fcec5f6..76c7cb9c2 100644
--- a/system/database/drivers/mssql/mssql_utility.php
+++ b/system/database/drivers/mssql/mssql_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MS SQL Utility Class
@@ -34,19 +35,30 @@
  */
 class CI_DB_mssql_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'EXEC sp_helpdb'; // Can also be: EXEC sp_databases
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= 'ALTER INDEX all ON %s REORGANIZE';
 
 	/**
-	 * MSSQL Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	bool
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index f82e775e6..b1edc2925 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQL Database Adapter Class
@@ -40,25 +41,46 @@
  */
 class CI_DB_mysql_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'mysql';
-	public $compress = FALSE;
 
-	// The character used for escaping
-	protected $_escape_char = '`';
-
-	protected $_random_keyword = ' RAND()'; // database specific random keyword
+	/**
+	 * Compression flag
+	 *
+	 * @var	bool
+	 */
+	public $compress = FALSE;
 
 	/**
+	 * DELETE hack flag
+	 *
 	 * Whether to use the MySQL "delete hack" which allows the number
 	 * of affected rows to be shown. Uses a preg_replace when enabled,
 	 * adding a bit more processing to all queries.
+	 *
+	 * @var	bool
 	 */
 	public $delete_hack = TRUE;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Identifier escape character
 	 *
-	 * @param	array
+	 * @var	string
+	 */
+	protected $_escape_char = '`';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -76,7 +98,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Non-persistent database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	resource
 	 */
 	public function db_connect($persistent = FALSE)
@@ -128,7 +150,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Select the database
 	 *
-	 * @param	string	database name
+	 * @param	string	$database
 	 * @return	bool
 	 */
 	public function db_select($database = '')
@@ -152,7 +174,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Set client character set
 	 *
-	 * @param	string
+	 * @param	string	$charset
 	 * @return	bool
 	 */
 	protected function _db_set_charset($charset)
@@ -169,9 +191,21 @@ class CI_DB_mysql_driver extends CI_DB {
 	 */
 	public function version()
 	{
-		return isset($this->data_cache['version'])
-			? $this->data_cache['version']
-			: $this->data_cache['version'] = @mysql_get_server_info($this->conn_id);
+		if (isset($this->data_cache['version']))
+		{
+			return $this->data_cache['version'];
+		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
+
+		if ( ! $this->conn_id OR ($version = @mysql_get_server_info($this->conn_id)) === FALSE)
+		{
+			return FALSE;
+		}
+
+		return $this->data_cache['version'] = $version;
 	}
 
 	// --------------------------------------------------------------------
@@ -179,7 +213,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	mixed
 	 */
 	protected function _execute($sql)
@@ -194,7 +228,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	 *
 	 * If needed, each database adapter can prep the query string
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	string
 	 */
 	protected function _prep_query($sql)
@@ -214,7 +248,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -280,8 +314,8 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -340,7 +374,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -362,7 +396,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -375,7 +409,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Returns an object with field data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	object
 	 */
 	public function field_data($table = '')
@@ -426,9 +460,9 @@ class CI_DB_mysql_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
diff --git a/system/database/drivers/mysql/mysql_forge.php b/system/database/drivers/mysql/mysql_forge.php
index 2ac75bad2..6c5dfc665 100644
--- a/system/database/drivers/mysql/mysql_forge.php
+++ b/system/database/drivers/mysql/mysql_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQL Forge Class
@@ -34,165 +35,167 @@
  */
 class CI_DB_mysql_forge extends CI_DB_forge {
 
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_create_database	= 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';
 
 	/**
-	 * Process Fields
+	 * CREATE TABLE keys flag
 	 *
-	 * @param	mixed	the fields
-	 * @return	string
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
 	 */
-	protected function _process_fields($fields)
-	{
-		$current_field_count = 0;
-		$sql = '';
-
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field);
-
-				empty($attributes['NAME']) OR $sql .= ' '.$this->db->escape_identifiers($attributes['NAME']).' ';
-
-				if ( ! empty($attributes['TYPE']))
-				{
-					$sql .=  ' '.$attributes['TYPE'];
-
-					if ( ! empty($attributes['CONSTRAINT']))
-					{
-						switch (strtolower($attributes['TYPE']))
-						{
-							case 'decimal':
-							case 'float':
-							case 'numeric':
-								$sql .= '('.implode(',', $attributes['CONSTRAINT']).')';
-								break;
-							case 'enum':
-							case 'set':
-								$sql .= '("'.implode('","', $attributes['CONSTRAINT']).'")';
-								break;
-							default:
-								$sql .= '('.$attributes['CONSTRAINT'].')';
-						}
-					}
-				}
+	protected $_create_table_keys	= TRUE;
 
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT',
+		'SMALLINT',
+		'MEDIUMINT',
+		'INT',
+		'INTEGER',
+		'BIGINT',
+		'REAL',
+		'DOUBLE',
+		'DOUBLE PRECISION',
+		'FLOAT',
+		'DECIMAL',
+		'NUMERIC'
+	);
 
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	// --------------------------------------------------------------------
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
 
-		return $sql;
+		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * ALTER TABLE
 	 *
-	 * @param	string	the table name
-	 * @param	mixed	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _alter_table($alter_type, $table, $field)
 	{
-		$sql = 'CREATE TABLE ';
-
-		if ($if_not_exists === TRUE)
-		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' ('.$this->_process_fields($fields);
-
-		if (count($primary_keys) > 0)
+		if ($alter_type === 'DROP')
 		{
-			$key_name = $this->db->escape_identifiers(implode('_', $primary_keys));
-			$sql .= ",\n\tPRIMARY KEY ".$key_name.' ('.implode(', ', $this->db->escape_identifiers($primary_keys)).')';
+			return parent::_alter_table($alter_type, $table, $field);
 		}
 
-		if (is_array($keys) && count($keys) > 0)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			foreach ($keys as $key)
+			if ($field[$i]['_literal'] !== FALSE)
 			{
-				if (is_array($key))
+				$field[$i] = ($alter_type === 'ADD')
+						? "\n\tADD ".$field[$i]['_literal']
+						: "\n\tMODIFY ".$field[$i]['_literal'];
+			}
+			else
+			{
+				if ($alter_type === 'ADD')
 				{
-					$key_name = $this->db->escape_identifiers(implode('_', $key));
-					$key = $this->db->escape_identifiers($key);
+					$field[$i]['_literal'] = "\n\tADD ";
 				}
 				else
 				{
-					$key_name = $this->db->escape_identifiers($key);
-					$key = array($key_name);
+					$field[$i]['_literal'] = empty($field[$i]['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
 				}
 
-				$sql .= ",\n\tKEY ".$key_name.' ('.implode(', ', $key).')';
+				$field[$i] = $field[$i]['_literal'].$this->_process_column($field[$i]);
 			}
 		}
 
-		return $sql."\n) DEFAULT CHARACTER SET ".$this->db->char_set.' COLLATE '.$this->db->dbcollat.';';
+		return array($sql.implode(',', $field));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Process column
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column() and column_alter()
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		$extra_clause = isset($field['after'])
+			? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';
+
+		if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
+		{
+			$extra_clause = ' FIRST';
+		}
+
+		return $this->db->escape_identifiers($field['name'])
+			.(empty($field['new_name']) ? '' : $this->db->escape_identifiers($field['new_name']))
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['null']
+			.$field['default']
+			.$field['auto_increment']
+			.$field['unique']
+			.$extra_clause;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process indexes
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	array	fields
-	 * @param	string	the field after which we should add the new field
+	 * @param	string	$table	(ignored)
 	 * @return	string
 	 */
-	protected function _alter_table($alter_type, $table, $fields, $after_field = '')
+	protected function _process_indexes($table = NULL)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' ';
+		$sql = '';
 
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
 		{
-			return $sql.$this->db->escape_identifiers($fields);
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
 		}
 
-		return $sql.$this->_process_fields($fields)
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+		$this->keys = array();
+
+		return $sql;
 	}
 
 }
diff --git a/system/database/drivers/mysql/mysql_result.php b/system/database/drivers/mysql/mysql_result.php
index b3f669e40..4bfa0ae35 100644
--- a/system/database/drivers/mysql/mysql_result.php
+++ b/system/database/drivers/mysql/mysql_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQL Result Class
@@ -38,9 +39,9 @@
 class CI_DB_mysql_result extends CI_DB_result {
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
-	 * @param	object
+	 * @param	object	&$driver_object
 	 * @return	void
 	 */
 	public function __construct(&$driver_object)
@@ -144,9 +145,9 @@ class CI_DB_mysql_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -177,7 +178,7 @@ class CI_DB_mysql_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/mysql/mysql_utility.php b/system/database/drivers/mysql/mysql_utility.php
index f0bbc665e..8aa051755 100644
--- a/system/database/drivers/mysql/mysql_utility.php
+++ b/system/database/drivers/mysql/mysql_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQL Utility Class
@@ -34,14 +35,33 @@
  */
 class CI_DB_mysql_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'SHOW DATABASES';
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= 'OPTIMIZE TABLE %s';
+
+	/**
+	 * REPAIR TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_repair_table	= 'REPAIR TABLE %s';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * MySQL Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index 6c4f87513..ae17703ac 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQLi Database Adapter Class
@@ -40,25 +41,46 @@
  */
 class CI_DB_mysqli_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'mysqli';
-	public $compress = FALSE;
 
-	// The character used for escaping
-	protected $_escape_char = '`';
-
-	protected $_random_keyword = ' RAND()'; // database specific random keyword
+	/**
+	 * Compression flag
+	 *
+	 * @var	bool
+	 */
+	public $compress = FALSE;
 
 	/**
+	 * DELETE hack flag
+	 *
 	 * Whether to use the MySQL "delete hack" which allows the number
 	 * of affected rows to be shown. Uses a preg_replace when enabled,
 	 * adding a bit more processing to all queries.
+	 *
+	 * @var	bool
 	 */
 	public $delete_hack = TRUE;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Non-persistent database connection
+	 * Identifier escape character
 	 *
-	 * @param	bool
+	 * @var	string
+	 */
+	protected $_escape_char = '`';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Database connection
+	 *
+	 * @param	bool	$persistent
 	 * @return	object
 	 * @todo	SSL support
 	 */
@@ -110,7 +132,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Select the database
 	 *
-	 * @param	string	database name
+	 * @param	string	$database
 	 * @return	bool
 	 */
 	public function db_select($database = '')
@@ -134,7 +156,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Set client character set
 	 *
-	 * @param	string
+	 * @param	string	$charset
 	 * @return	bool
 	 */
 	protected function _db_set_charset($charset)
@@ -151,9 +173,16 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 */
 	public function version()
 	{
-		return isset($this->data_cache['version'])
-			? $this->data_cache['version']
-			: $this->data_cache['version'] = $this->conn_id->server_info;
+		if (isset($this->data_cache['version']))
+		{
+			return $this->data_cache['version'];
+		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
+
+		return $this->data_cache['version'] = $this->conn_id->server_info;
 	}
 
 	// --------------------------------------------------------------------
@@ -161,7 +190,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	mixed
 	 */
 	protected function _execute($sql)
@@ -176,7 +205,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * If needed, each database adapter can prep the query string
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	string
 	 */
 	protected function _prep_query($sql)
@@ -196,7 +225,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -262,8 +291,8 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -322,7 +351,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -344,7 +373,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -357,7 +386,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Returns an object with field data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	object
 	 */
 	public function field_data($table = '')
@@ -416,9 +445,9 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index b74c775b2..a70eef88f 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQLi Forge Class
@@ -34,165 +35,167 @@
  */
 class CI_DB_mysqli_forge extends CI_DB_forge {
 
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_create_database	= 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';
 
 	/**
-	 * Process Fields
+	 * CREATE TABLE keys flag
 	 *
-	 * @param	mixed	the fields
-	 * @return	string
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
 	 */
-	protected function _process_fields($fields)
-	{
-		$current_field_count = 0;
-		$sql = '';
-
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field);
-
-				empty($attributes['NAME']) OR $sql .= ' '.$this->db->escape_identifiers($attributes['NAME']).' ';
-
-				if ( ! empty($attributes['TYPE']))
-				{
-					$sql .= ' '.$attributes['TYPE'];
-
-					if ( ! empty($attributes['CONSTRAINT']))
-					{
-						switch (strtolower($attributes['TYPE']))
-						{
-							case 'decimal':
-							case 'float':
-							case 'numeric':
-								$sql .= '('.implode(',', $attributes['CONSTRAINT']).')';
-								break;
-							case 'enum':
-							case 'set':
-								$sql .= '("'.implode('","', $attributes['CONSTRAINT']).'")';
-								break;
-							default:
-								$sql .= '('.$attributes['CONSTRAINT'].')';
-						}
-					}
-				}
+	protected $_create_table_keys	= TRUE;
 
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT',
+		'SMALLINT',
+		'MEDIUMINT',
+		'INT',
+		'INTEGER',
+		'BIGINT',
+		'REAL',
+		'DOUBLE',
+		'DOUBLE PRECISION',
+		'FLOAT',
+		'DECIMAL',
+		'NUMERIC'
+	);
 
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	// --------------------------------------------------------------------
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
 
-		return $sql;
+		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * ALTER TABLE
 	 *
-	 * @param	string	the table name
-	 * @param	mixed	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _alter_table($alter_type, $table, $field)
 	{
-		$sql = 'CREATE TABLE ';
-
-		if ($if_not_exists === TRUE)
-		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' ('.$this->_process_fields($fields);
-
-		if (count($primary_keys) > 0)
+		if ($alter_type === 'DROP')
 		{
-			$key_name = $this->db->escape_identifiers(implode('_', $primary_keys));
-			$sql .= ",\n\tPRIMARY KEY ".$key_name.' ('.implode(', ', $this->db->escape_identifiers($primary_keys)).')';
+			return parent::_alter_table($alter_type, $table, $field);
 		}
 
-		if (is_array($keys) && count($keys) > 0)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			foreach ($keys as $key)
+			if ($field[$i]['_literal'] !== FALSE)
 			{
-				if (is_array($key))
+				$field[$i] = ($alter_type === 'ADD')
+						? "\n\tADD ".$field[$i]['_literal']
+						: "\n\tMODIFY ".$field[$i]['_literal'];
+			}
+			else
+			{
+				if ($alter_type === 'ADD')
 				{
-					$key_name = $this->db->escape_identifiers(implode('_', $key));
-					$key = $this->db->escape_identifiers($key);
+					$field[$i]['_literal'] = "\n\tADD ";
 				}
 				else
 				{
-					$key_name = $this->db->escape_identifiers($key);
-					$key = array($key_name);
+					$field[$i]['_literal'] = empty($field[$i]['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
 				}
 
-				$sql .= ",\n\tKEY ".$key_name.' ('.implode(', ', $key).')';
+				$field[$i] = $field[$i]['_literal'].$this->_process_column($field[$i]);
 			}
 		}
 
-		return $sql."\n) DEFAULT CHARACTER SET ".$this->db->char_set.' COLLATE '.$this->db->dbcollat.';';
+		return array($sql.implode(',', $field));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Process column
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		$extra_clause = isset($field['after'])
+			? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';
+
+		if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
+		{
+			$extra_clause = ' FIRST';
+		}
+
+		return $this->db->escape_identifiers($field['name'])
+			.(empty($field['new_name']) ? '' : $this->db->escape_identifiers($field['new_name']))
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['null']
+			.$field['default']
+			.$field['auto_increment']
+			.$field['unique']
+			.$extra_clause;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process indexes
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	array	fields
-	 * @param	string	the field after which we should add the new field
+	 * @param	string	$table	(ignored)
 	 * @return	string
 	 */
-	protected function _alter_table($alter_type, $table, $fields, $after_field = '')
+	protected function _process_indexes($table = NULL)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' ';
+		$sql = '';
 
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
 		{
-			return $sql.$this->db->escape_identifiers($fields);
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
 		}
 
-		return $sql.$this->_process_fields($fields)
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+		$this->keys = array();
+
+		return $sql;
 	}
 
 }
diff --git a/system/database/drivers/mysqli/mysqli_result.php b/system/database/drivers/mysqli/mysqli_result.php
index f036302bb..15e15cd5f 100644
--- a/system/database/drivers/mysqli/mysqli_result.php
+++ b/system/database/drivers/mysqli/mysqli_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQLi Result Class
@@ -130,9 +131,9 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -161,7 +162,7 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/mysqli/mysqli_utility.php b/system/database/drivers/mysqli/mysqli_utility.php
index 5d2bdbce0..345691e84 100644
--- a/system/database/drivers/mysqli/mysqli_utility.php
+++ b/system/database/drivers/mysqli/mysqli_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * MySQLi Utility Class
@@ -34,14 +35,33 @@
  */
 class CI_DB_mysqli_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'SHOW DATABASES';
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= 'OPTIMIZE TABLE %s';
+
+	/**
+	 * REPAIR TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_repair_table	= 'REPAIR TABLE %s';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * MySQLi Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index 81d73d073..eb01dd17e 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * oci8 Database Adapter Class
@@ -49,34 +50,76 @@
  */
 class CI_DB_oci8_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'oci8';
 
-	// The character used for excaping
-	protected $_escape_char = '"';
+	/**
+	 * Statement ID
+	 *
+	 * @var	resource
+	 */
+	public $stmt_id;
 
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * Cursor ID
+	 *
+	 * @var	resource
 	 */
-	protected $_count_string = 'SELECT COUNT(1) AS ';
-	protected $_random_keyword = ' ASC'; // not currently supported
+	public $curs_id;
+
+	/**
+	 * Commit mode flag
+	 *
+	 * @var	int
+	 */
+	public $commit_mode = OCI_COMMIT_ON_SUCCESS;
 
+	/**
+	 * Limit used flag
+	 *
+	 * If we use LIMIT, we'll add a field that will
+	 * throw off num_fields later.
+	 *
+	 * @var	bool
+	 */
+	public $limit_used;
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * List of reserved identifiers
+	 *
+	 * Identifiers that must NOT be escaped.
+	 *
+	 * @var	string[]
+	 */
 	protected $_reserved_identifiers = array('*', 'rownum');
 
-	// Set "auto commit" by default
-	public $commit_mode = OCI_COMMIT_ON_SUCCESS;
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' ASC'; // not currently supported
 
-	// need to track statement id and cursor id
-	public $stmt_id;
-	public $curs_id;
+	/**
+	 * COUNT string
+	 *
+	 * @used-by	CI_DB_driver::count_all()
+	 * @used-by	CI_DB_query_builder::count_all_results()
+	 *
+	 * @var	string
+	 */
+	protected $_count_string = 'SELECT COUNT(1) AS ';
 
-	// if we use a limit, we will add a field that will
-	// throw off num_fields later
-	public $limit_used;
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * @param	array	$params
 	 * @return	void
@@ -197,9 +240,21 @@ class CI_DB_oci8_driver extends CI_DB {
 	 */
 	public function version()
 	{
-		return isset($this->data_cache['version'])
-			? $this->data_cache['version']
-			: $this->data_cache['version'] = oci_server_version($this->conn_id);
+		if (isset($this->data_cache['version']))
+		{
+			return $this->data_cache['version'];
+		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
+
+		if ( ! $this->conn_id OR ($version = oci_server_version($this->conn_id)) === FALSE)
+		{
+			return FALSE;
+		}
+
+		return $this->data_cache['version'] = $version;
 	}
 
 	// --------------------------------------------------------------------
@@ -207,7 +262,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -226,7 +281,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	/**
 	 * Generate a statement ID
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	void
 	 */
 	protected function _set_stmt_id($sql)
@@ -306,7 +361,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	/**
 	 * Bind parameters
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	protected function _bind_params($params)
@@ -335,7 +390,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -408,8 +463,8 @@ class CI_DB_oci8_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -469,7 +524,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -492,7 +547,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -507,7 +562,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -549,13 +604,13 @@ class CI_DB_oci8_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert_batch statement
+	 * Insert batch statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param 	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param 	array	$values	INSERT values
 	 * @return	string
 	 */
 	protected function _insert_batch($table, $keys, $values)
@@ -578,10 +633,10 @@ class CI_DB_oci8_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -596,7 +651,7 @@ class CI_DB_oci8_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -613,11 +668,11 @@ class CI_DB_oci8_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/oci8/oci8_forge.php b/system/database/drivers/oci8/oci8_forge.php
index 92e8c02ed..bd9d2df3c 100644
--- a/system/database/drivers/oci8/oci8_forge.php
+++ b/system/database/drivers/oci8/oci8_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Oracle Forge Class
@@ -34,122 +35,96 @@
  */
 class CI_DB_oci8_forge extends CI_DB_forge {
 
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_create_database	= FALSE;
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
 	protected $_drop_database	= FALSE;
-	protected $_drop_table		= 'DROP TABLE %s';
 
 	/**
-	 * Create Table
+	 * DROP TABLE IF statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	string
+	 * @var	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = 'CREATE TABLE ';
+	protected $_drop_table_if	= FALSE;
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
 
-		if ($if_not_exists === TRUE)
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'DROP')
 		{
-			$sql .= 'IF NOT EXISTS ';
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+		elseif ($alter_type === 'CHANGE')
+		{
+			$alter_type = 'MODIFY';
 		}
 
-		$sql .= $this->db->escape_identifiers($table).' (';
-		$current_field_count = 0;
-
-		foreach ($fields as $field => $attributes)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
+			if ($field[$i]['_literal'] !== FALSE)
 			{
-				$sql .= "\n\t".$attributes;
+				$field[$i] = "\n\t".$field[$i]['_literal'];
 			}
 			else
 			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				if (isset($attributes['UNSINGED']) && $attributes['UNSIGNED'] === TRUE)
+				$field[$i]['_literal'] = "\n\t".$this->_process_column($field[$i]);
+				if ($alter_type === 'MODIFY' && ! empty($field[$i]['new_name']))
 				{
-					$sql .= ' UNSIGNED';
+					$sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
+						.' '.$this->db->escape_identifiers($field[$i]['new_name']);
 				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= (isset($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? '' : ' NOT NULL';
-
-				empty($attributes['CONSTRAINT']) OR ' CONSTRAINT '.$attributes['CONSTRAINT'];
-			}
-
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
 			}
 		}
 
-		if (count($primary_keys) > 0)
-		{
-			$sql .= ",\n\tCONSTRAINT ".$table.' PRIMARY KEY ('.implode(', ', $this->db->escape_identifiers($primary_keys)).')';
-		}
+		$sql .= ' '.$alter_type.' ';
+		$sql .= (count($field) === 1)
+				? $fields[0]
+				: '('.implode(',', $field).')';
 
-		if (is_array($keys) && count($keys) > 0)
-		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tUNIQUE COLUMNS (".implode(', ', $key).')';
-			}
-		}
-
-		return $sql."\n)";
+		// RENAME COLUMN must be executed after MODIFY
+		array_unshift($sqls, $sql);
+		return $sql;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
-	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Field attribute AUTO_INCREMENT
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_auto_increment(&$attributes, &$field)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name);
-
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
-		{
-			return $sql;
-		}
-
-		return $sql.' '.$column_definition
-			.($default_value !== '' ? ' DEFAULT "'.$default_value.'"' : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
-
+		// Not supported - sequences and triggers must be used instead
 	}
 
 }
diff --git a/system/database/drivers/oci8/oci8_result.php b/system/database/drivers/oci8/oci8_result.php
index ade186be7..7d5bf5172 100644
--- a/system/database/drivers/oci8/oci8_result.php
+++ b/system/database/drivers/oci8/oci8_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * oci8 Result Class
@@ -37,15 +38,40 @@
  */
 class CI_DB_oci8_result extends CI_DB_result {
 
+	/**
+	 * Statement ID
+	 *
+	 * @var	resource
+	 */
 	public $stmt_id;
+
+	/**
+	 * Cursor ID
+	 *
+	 * @var	resource
+	 */
 	public $curs_id;
+
+	/**
+	 * Limit used flag
+	 *
+	 * @var	bool
+	 */
 	public $limit_used;
+
+	/**
+	 * Commit mode flag
+	 *
+	 * @var	int
+	 */
 	public $commit_mode;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
-	 * @param	object
+	 * @param	object	&$driver_object
 	 * @return	void
 	 */
 	public function __construct(&$driver_object)
@@ -167,7 +193,7 @@ class CI_DB_oci8_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
@@ -211,9 +237,10 @@ class CI_DB_oci8_result extends CI_DB_result {
 	 * some point in the future, but it will only work for resetting the
 	 * pointer to zero.
 	 *
+	 * @param	int	$n	(ignored)
 	 * @return	bool
 	 */
-	protected function _data_seek()
+	protected function _data_seek($n = 0)
 	{
 		/* The PHP manual says that if OCI_NO_AUTO_COMMIT mode
 		 * is used, and oci_rollback() and/or oci_commit() are
diff --git a/system/database/drivers/oci8/oci8_utility.php b/system/database/drivers/oci8/oci8_utility.php
index 0183eda26..d15537fdf 100644
--- a/system/database/drivers/oci8/oci8_utility.php
+++ b/system/database/drivers/oci8/oci8_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Oracle Utility Class
@@ -34,18 +35,23 @@
  */
 class CI_DB_oci8_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'SELECT username FROM dba_users'; // Schemas are actual usernames
 
 	/**
-	 * Oracle Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index f6ea412ad..1710aafae 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * ODBC Database Adapter Class
@@ -40,24 +41,42 @@
  */
 class CI_DB_odbc_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'odbc';
 
-	// the character used to excape - not necessary for ODBC
-	protected $_escape_char = '';
+	/**
+	 * Database schema
+	 *
+	 * @var	string
+	 */
+	public $schema = 'public';
 
-	protected $_like_escape_str = " {escape '%s'} ";
+	// --------------------------------------------------------------------
 
-	protected $_random_keyword;
+	/**
+	 * Identifier escape character
+	 *
+	 * Must be empty for ODBC.
+	 *
+	 * @var	string
+	 */
+	protected $_escape_char = '';
 
 	/**
-	 * Database schema
+	 * ESCAPE statement string
 	 *
 	 * @var	string
 	 */
-	public $schema = 'public';
+	protected $_like_escape_str = " {escape '%s'} ";
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * @param	array	$params
 	 * @return	void
@@ -104,7 +123,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -117,7 +136,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -181,8 +200,8 @@ class CI_DB_odbc_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -231,7 +250,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 */
 	public function insert_id()
 	{
-		return ($this->db->db_debug) ? $this->db->display_error('db_unsuported_feature') : FALSE;
+		return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -241,7 +260,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -264,7 +283,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -279,7 +298,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -309,8 +328,8 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -327,10 +346,10 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -345,7 +364,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
diff --git a/system/database/drivers/odbc/odbc_forge.php b/system/database/drivers/odbc/odbc_forge.php
index d17b046ee..fb16ca5cf 100644
--- a/system/database/drivers/odbc/odbc_forge.php
+++ b/system/database/drivers/odbc/odbc_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * ODBC Forge Class
@@ -34,124 +35,39 @@
  */
 class CI_DB_odbc_forge extends CI_DB_forge {
 
-	protected $_drop_table		= 'DROP TABLE %s';
-
 	/**
-	 * Create Table
+	 * CREATE TABLE IF statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @var	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = 'CREATE TABLE ';
-
-		if ($if_not_exists === TRUE)
-		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' (';
-		$current_field_count = 0;
-
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				empty($attributes['CONSTRAINT']) OR $sql .= '('.$attributes['CONSTRAINT'].')';
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
-
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
-
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	protected $_create_table_if	= FALSE;
 
-		if (count($primary_keys) > 0)
-		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->escape_identifiers($primary_keys)).')';
-		}
-
-		if (is_array($keys) && count($keys) > 0)
-		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';
-			}
-		}
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= FALSE;
 
-		return $sql."\n)";
-	}
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute AUTO_INCREMENT
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
-	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_auto_increment(&$attributes, &$field)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name);
-
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
-		{
-			return $sql;
-		}
-
-		return $sql.' '.$column_definition
-			.($default_value != '' ? ' DEFAULT "'.$default_value.'"' : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field != '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+		// Not supported (in most databases at least)
 	}
 
 }
diff --git a/system/database/drivers/odbc/odbc_result.php b/system/database/drivers/odbc/odbc_result.php
index 48dc48dd9..2c50c255b 100644
--- a/system/database/drivers/odbc/odbc_result.php
+++ b/system/database/drivers/odbc/odbc_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * ODBC Result Class
@@ -165,7 +166,7 @@ class CI_DB_odbc_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
@@ -198,11 +199,11 @@ if ( ! function_exists('odbc_fetch_array'))
 	 * Emulates the native odbc_fetch_array() function when
 	 * it is not available (odbc_fetch_array() requires unixODBC)
 	 *
-	 * @param	resource
-	 * @param	int
+	 * @param	resource	&$result
+	 * @param	int		$rownumber
 	 * @return	array
 	 */
-	function odbc_fetch_array(& $result, $rownumber = 1)
+	function odbc_fetch_array(&$result, $rownumber = 1)
 	{
 		$rs = array();
 		if ( ! odbc_fetch_into($result, $rs, $rownumber))
@@ -231,11 +232,11 @@ if ( ! function_exists('odbc_fetch_object'))
 	 * Emulates the native odbc_fetch_object() function when
 	 * it is not available.
 	 *
-	 * @param	resource
-	 * @param	int
+	 * @param	resource	&$result
+	 * @param	int		$rownumber
 	 * @return	object
 	 */
-	function odbc_fetch_object(& $result, $rownumber = 1)
+	function odbc_fetch_object(&$result, $rownumber = 1)
 	{
 		$rs = array();
 		if ( ! odbc_fetch_into($result, $rs, $rownumber))
diff --git a/system/database/drivers/odbc/odbc_utility.php b/system/database/drivers/odbc/odbc_utility.php
index 224d48d2b..908674a9d 100644
--- a/system/database/drivers/odbc/odbc_utility.php
+++ b/system/database/drivers/odbc/odbc_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * ODBC Utility Class
@@ -34,18 +35,16 @@
  */
 class CI_DB_odbc_utility extends CI_DB_utility {
 
-	protected $_list_databases	= FALSE;
-
 	/**
-	 * ODBC Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 32a9e7509..923f0e125 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Database Adapter Class
@@ -40,22 +41,33 @@
  */
 class CI_DB_pdo_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'pdo';
 
-	// The character used to escaping
-	protected $_escape_char = '"';
-
-	protected $_random_keyword;
-
+	/**
+	 * Transaction enabled flag
+	 *
+	 * @var	bool
+	 */
 	public $trans_enabled = FALSE;
 
-	// need to track the PDO options
+	/**
+	 * PDO Options
+	 *
+	 * @var	array
+	 */
 	public $options = array();
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
-	 * Validates the DSN string and/or detects the subdriver
+	 * Validates the DSN string and/or detects the subdriver.
 	 *
 	 * @param	array	$params
 	 * @return	void
@@ -103,9 +115,9 @@ class CI_DB_pdo_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
@@ -153,6 +165,10 @@ class CI_DB_pdo_driver extends CI_DB {
 		{
 			return $this->data_cache['version'];
 		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
 
 		// Not all subdrivers support the getAttribute() method
 		try
@@ -170,7 +186,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	SQL query
 	 * @return	mixed
 	 */
 	protected function _execute($sql)
@@ -183,7 +199,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -243,8 +259,8 @@ class CI_DB_pdo_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -296,7 +312,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	/**
 	 * Insert ID
 	 *
-	 * @param	string
+	 * @param	string	$name
 	 * @return	int
 	 */
 	public function insert_id($name = NULL)
@@ -311,7 +327,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -355,9 +371,9 @@ class CI_DB_pdo_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -401,10 +417,10 @@ class CI_DB_pdo_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -415,4 +431,4 @@ class CI_DB_pdo_driver extends CI_DB {
 }
 
 /* End of file pdo_driver.php */
-/* Location: ./system/database/drivers/pdo/pdo_driver.php */
+/* Location: ./system/database/drivers/pdo/pdo_driver.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/pdo_forge.php b/system/database/drivers/pdo/pdo_forge.php
index 34a6ee44e..130d3667e 100644
--- a/system/database/drivers/pdo/pdo_forge.php
+++ b/system/database/drivers/pdo/pdo_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Forge Class
@@ -34,133 +35,19 @@
  */
 class CI_DB_pdo_forge extends CI_DB_forge {
 
-	protected $_drop_table		= 'DROP TABLE %s';
-
 	/**
-	 * Create Table
+	 * CREATE TABLE IF statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @var	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = 'CREATE TABLE ';
-
-		if ($if_not_exists === TRUE)
-		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' (';
-		$current_field_count = 0;
-
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-				$numeric = array('SERIAL', 'INTEGER');
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				if ( ! empty($attributes['CONSTRAINT']))
-				{
-					// Exception for Postgre numeric which not too happy with constraint within those type
-					if ( ! ($this->db->subdriver === 'pgsql' && in_array($attributes['TYPE'], $numeric)))
-					{
-						$sql .= '('.$attributes['CONSTRAINT'].')';
-					}
-				}
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
-
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
-
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
-
-		if (count($primary_keys) > 0)
-		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
-		}
-
-		if (is_array($keys) && count($keys) > 0)
-		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';
-			}
-		}
-
-		return $sql."\n)";
-	}
-
-	// --------------------------------------------------------------------
+	protected $_create_table_if	= FALSE;
 
 	/**
-	 * Alter table query
-	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * DROP TABLE IF statement
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @var	string
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
-	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name);
-
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
-		{
-			return $sql;
-		}
-
-		return $sql .' '.$column_definition
-			.($default_value !== '' ? " DEFAULT '".$default_value."'" : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
-	}
+	protected $_drop_table_if	= FALSE;
 
 }
 
diff --git a/system/database/drivers/pdo/pdo_result.php b/system/database/drivers/pdo/pdo_result.php
index 444406986..32ab1c280 100644
--- a/system/database/drivers/pdo/pdo_result.php
+++ b/system/database/drivers/pdo/pdo_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Result Class
@@ -162,7 +163,7 @@ class CI_DB_pdo_result extends CI_DB_result {
 		{
 			if ($this->db->db_debug)
 			{
-				return $this->db->display_error('db_unsuported_feature');
+				return $this->db->display_error('db_unsupported_feature');
 			}
 
 			return FALSE;
@@ -205,7 +206,7 @@ class CI_DB_pdo_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/pdo/pdo_utility.php b/system/database/drivers/pdo/pdo_utility.php
index 930842118..86f2b120a 100644
--- a/system/database/drivers/pdo/pdo_utility.php
+++ b/system/database/drivers/pdo/pdo_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Utility Class
@@ -34,18 +35,16 @@
  */
 class CI_DB_pdo_utility extends CI_DB_utility {
 
-	protected $_list_databases = FALSE;
-
 	/**
-	 * PDO Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
index 438d312a1..6ebd92a9b 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO 4D Database Adapter Class
@@ -40,19 +41,28 @@
  */
 class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = '4d';
 
-	// The character used for escaping
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string[]
+	 */
 	protected $_escape_char = array('[', ']');
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -80,7 +90,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -103,7 +113,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -119,7 +129,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -134,8 +144,8 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -152,7 +162,7 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -164,11 +174,11 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_forge.php b/system/database/drivers/pdo/subdrivers/pdo_4d_forge.php
new file mode 100644
index 000000000..231ad53a4
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_forge.php
@@ -0,0 +1,209 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO 4D Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_4d_forge extends CI_DB_4d_forge {
+
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_database	= 'CREATE SCHEMA %s';
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_database	= 'DROP SCHEMA %s';
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= 'CREATE TABLE IF NOT EXISTS';
+
+	/**
+	 * RENAME TABLE statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= FALSE;
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'INT16'		=> 'INT',
+		'SMALLINT'	=> 'INT',
+		'INT'		=> 'INT64',
+		'INT32'		=> 'INT64'
+	);
+
+	/**
+	 * DEFAULT value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_default		= FALSE;
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('ADD', 'DROP'), TRUE))
+		{
+			return parent::_alter_table($alter_table, $table, $field);
+		}
+
+		// No method of modifying columns is supported
+		return FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type'].$field['length']
+			.$field['null']
+			.$field['unique']
+			.$field['auto_increment'];
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INTEGER':
+				$attributes['TYPE'] = 'INT';
+				return;
+			case 'BIGINT':
+				$attribites['TYPE'] = 'INT64';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute UNIQUE
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_unique(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
+		{
+			$field['unique'] = ' UNIQUE';
+
+			// UNIQUE must be used with NOT NULL
+			$field['null'] = ' NOT NULL';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
+		{
+			if (stripos($field['type'], 'int') !== FALSE)
+			{
+				$field['auto_increment'] = ' AUTO_INCREMENT';
+			}
+			elseif (strcasecmp($field['type'], 'UUID') === 0)
+			{
+				$field['auto_increment'] = ' AUTO_GENERATE';
+			}
+		}
+	}
+
+}
+
+/* End of file pdo_4d_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_4d_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index d2a484d9e..4f762b91c 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO CUBRID Database Adapter Class
@@ -40,18 +41,28 @@
  */
 class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'cubrid';
 
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
 	protected $_escape_char = '`';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -75,7 +86,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -97,7 +108,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -112,7 +123,7 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -127,9 +138,9 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -168,10 +179,10 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php
new file mode 100644
index 000000000..e8421ec41
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php
@@ -0,0 +1,212 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO CUBRID Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_cubrid_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_database	= FALSE;
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_database	= FALSE;
+
+	/**
+	 * CREATE TABLE keys flag
+	 *
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
+	 */
+	protected $_create_table_keys	= TRUE;
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SHORT'		=> 'INTEGER',
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT',
+		'BIGINT'	=> 'NUMERIC',
+		'FLOAT'		=> 'DOUBLE',
+		'REAL'		=> 'DOUBLE'
+	);
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				$sqls[] = $sql.' CHANGE '.$field[$i]['_literal'];
+			}
+			else
+			{
+				$sqls[] = $sql.' CHANGE '.$this->_process_column($field[$i]);
+				if ( ! empty($field[$i]['new_name']))
+				{
+					$sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
+						.' AS '.$this->db->escape_identifiers($field[$i]['name']);
+				}
+			}
+		}
+
+		return $sqls;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		$extra_clause = isset($field['after'])
+			? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';
+
+		if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
+		{
+			$extra_clause = ' FIRST';
+		}
+
+		return $this->db->escape_identifiers($field['name'])
+			.(empty($field['new_name']) ? '' : $this->db->escape_identifiers($field['new_name']))
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['null']
+			.$field['default']
+			.$field['auto_increment']
+			.$field['unique']
+			.$extra_clause;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process indexes
+	 *
+	 * @param	string	$table	(ignored)
+	 * @return	string
+	 */
+	protected function _process_indexes($table = NULL)
+	{
+		$sql = '';
+
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
+		{
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
+		}
+
+		$this->keys = array();
+
+		return $sql;
+	}
+
+}
+
+/* End of file pdo_cubrid_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_cubrid_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index 785b2795c..7121819ec 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO DBLIB Database Adapter Class
@@ -40,18 +41,40 @@
  */
 class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'dblib';
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -85,9 +108,9 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
@@ -115,7 +138,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -140,7 +163,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -157,8 +180,8 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -175,7 +198,7 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -191,11 +214,11 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
@@ -239,6 +262,29 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string|bool
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		// Multiple-value inserts are only supported as of SQL Server 2008
+		if (version_compare($this->version(), '10', '>='))
+		{
+			return parent::_insert_batch($table, $keys, $values);
+		}
+
+		return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+	}
+
 }
 
 /* End of file pdo_dblib_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php
new file mode 100644
index 000000000..236e1cce2
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php
@@ -0,0 +1,136 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO DBLIB Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_dblib_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT'	=> 'SMALLINT',
+		'SMALLINT'	=> 'INT',
+		'INT'		=> 'BIGINT',
+		'REAL'		=> 'FLOAT'
+	);
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('ADD', 'DROP'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' ALTER COLUMN ';
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
+		{
+			$sqls[] = $sql.$this->_process_column($field[$i]);
+		}
+
+		return $sqls;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INTEGER':
+				$attributes['TYPE'] = 'INT';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['auto_increment'] = ' IDENTITY(1,1)';
+		}
+	}
+
+}
+
+/* End of file pdo_dblib_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_dblib_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
index 32d1f219a..83b9648c1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Firebird Database Adapter Class
@@ -40,21 +41,30 @@
  */
 class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'firebird';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_random_keyword = ' RANDOM()'; // Currently not supported
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -90,7 +100,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -113,7 +123,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -128,7 +138,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -143,8 +153,8 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -160,10 +170,10 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
          */
 	protected function _truncate($table)
@@ -178,7 +188,7 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -190,11 +200,11 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php
new file mode 100644
index 000000000..474188f4e
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php
@@ -0,0 +1,228 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO Firebird Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_firebird_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * RENAME TABLE statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= FALSE;
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SMALLINT'	=> 'INTEGER',
+		'INTEGER'	=> 'INT64',
+		'FLOAT'		=> 'DOUBLE PRECISION'
+	);
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Create database
+	 *
+	 * @param	string	$db_name
+	 * @return	string
+	 */
+	public function create_database($db_name)
+	{
+		// Firebird databases are flat files, so a path is required
+
+		// Hostname is needed for remote access
+		empty($this->db->hostname) OR $db_name = $this->hostname.':'.$db_name;
+
+		return parent::create_database('"'.$db_name.'"');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Drop database
+	 *
+	 * @param	string	$db_name	(ignored)
+	 * @return	bool
+	 */
+	public function drop_database($db_name = '')
+	{
+		if ( ! ibase_drop_db($this->conn_id))
+		{
+			return ($this->db->db_debug) ? $this->db->display_error('db_unable_to_drop') : FALSE;
+		}
+		elseif ( ! empty($this->db->data_cache['db_names']))
+		{
+			$key = array_search(strtolower($this->db->database), array_map('strtolower', $this->db->data_cache['db_names']), TRUE);
+			if ($key !== FALSE)
+			{
+				unset($this->db->data_cache['db_names'][$key]);
+			}
+		}
+
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+ 	{
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field), $sql .= $alter_type.' '; $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				return FALSE;
+			}
+
+			if (isset($field[$i]['type']))
+			{
+				$sqls[] = $sql.' TYPE '.$field[$i]['type'].$field[$i]['length'];
+			}
+
+			if ( ! empty($field[$i]['default']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' SET '.$field[$i]['default'];
+			}
+
+			if (isset($field[$i]['null']))
+			{
+				$sqls[] = 'UPDATE "RDB$RELATION_FIELDS" SET "RDB$NULL_FLAG" = '
+					.($field[$i]['null'] === TRUE ? 'NULL' : '1')
+					.' WHERE "RDB$FIELD_NAME" = '.$this->db->escape($field[$i]['name'])
+					.' AND "RDB$RELATION_NAME" = '.$this->db->escape($table);
+			}
+
+			if ( ! empty($field[$i]['new_name']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' TO '.$this->db->escape_identifiers($field[$i]['new_name']);
+			}
+		}
+
+		return $sqls;
+ 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type'].$field['length']
+			.$field['null']
+			.$field['unique']
+			.$field['default'];
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INT':
+				$attributes['TYPE'] = 'INTEGER';
+				return;
+			case 'BIGINT':
+				$attributes['TYPE'] = 'INT64';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		// Not supported
+	}
+
+}
+
+/* End of file pdo_firebird_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_firebird_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
index 22a5f928c..d8dbc50c0 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO IBM DB2 Database Adapter Class
@@ -40,16 +41,21 @@
  */
 class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'ibm';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -115,7 +121,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -138,7 +144,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -154,7 +160,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -169,8 +175,8 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -187,7 +193,7 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -199,21 +205,19 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
-	 * @param	int	the number of rows to limit the query to
-	 * @param	int	the offset value
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		$sql .= ' FETCH FIRST '.($limit + $offset).' ROWS ONLY';
+		$sql .= ' FETCH FIRST '.($this->qb_limit + $this->qb_offset).' ROWS ONLY';
 
-		return ($offset)
-			? 'SELECT * FROM ('.$sql.') WHERE rownum > '.$offset
+		return ($this->qb_offset)
+			? 'SELECT * FROM ('.$sql.') WHERE rownum > '.$this->qb_offset
 			: $sql;
 	}
 
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_forge.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_forge.php
new file mode 100644
index 000000000..f095c717a
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_forge.php
@@ -0,0 +1,146 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO IBM DB2 Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_ibm_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * RENAME TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= 'RENAME TABLE %s TO %s';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT'
+	);
+
+	/**
+	 * DEFAULT value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_default		= FALSE;
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'CHANGE')
+		{
+			$alter_type = 'MODIFY';
+		}
+
+		return parent::_alter_table($alter_type, $table, $field);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute UNIQUE
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_unique(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
+		{
+			$field['unique'] = ' UNIQUE';
+
+			// UNIQUE must be used with NOT NULL
+			$field['null'] = ' NOT NULL';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		// Not supported
+	}
+
+}
+
+/* End of file pdo_ibm_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_ibm_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
index 8dd430184..8998670e1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Informix Database Adapter Class
@@ -40,16 +41,21 @@
  */
 class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'informix';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -108,7 +114,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -131,7 +137,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -148,7 +154,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -163,8 +169,8 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -181,10 +187,10 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -199,7 +205,7 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -211,11 +217,11 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	$SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_forge.php b/system/database/drivers/pdo/subdrivers/pdo_informix_forge.php
new file mode 100644
index 000000000..8722dd200
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_forge.php
@@ -0,0 +1,155 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO Informix Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_informix_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * RENAME TABLE statement
+	 *
+	 * @var	string
+	 */
+	protected $_rename_table	= 'RENAME TABLE %s TO %s';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT',
+		'REAL'		=> 'DOUBLE PRECISION',
+		'SMALLFLOAT'	=> 'DOUBLE PRECISION'
+	);
+
+	/**
+	 * DEFAULT value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_default		= ', ';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'CHANGE')
+		{
+			$alter_type = 'MODIFY';
+		}
+
+		return parent::_alter_table($alter_type, $table, $field);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'BYTE':
+			case 'TEXT':
+			case 'BLOB':
+			case 'CLOB':
+				$attributes['UNIQUE'] = FALSE;
+				if (isset($attributes['DEFAULT']))
+				{
+					unset($attributes['DEFAULT']);
+				}
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute UNIQUE
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_unique(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
+		{
+			$field['unique'] = ' UNIQUE CONSTRAINT '.$this->db->escape_identifiers($field['name']);
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		// Not supported
+	}
+
+}
+
+/* End of file pdo_informix_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_informix_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index 0fb5d8f12..2d076f314 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO MySQL Database Adapter Class
@@ -40,19 +41,37 @@
  */
 class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'mysql';
+
+	/**
+	 * Compression flag
+	 *
+	 * @var	bool
+	 */
 	public $compress = FALSE;
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Identifier escape character
+	 *
+	 * @var	string
+	 */
 	protected $_escape_char = '`';
 
-	protected $_random_keyword = ' RAND()';
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -76,9 +95,9 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 * @todo	SSL support
 	 */
@@ -110,7 +129,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -132,7 +151,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -147,7 +166,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -162,9 +181,9 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	UPDATE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -203,10 +222,10 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php
new file mode 100644
index 000000000..866b6fb21
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php
@@ -0,0 +1,218 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO MySQL Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_mysql_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_database	= 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= 'CREATE TABLE IF NOT EXISTS';
+
+	/**
+	 * CREATE TABLE keys flag
+	 *
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
+	 */
+	protected $_create_table_keys	= TRUE;
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT',
+		'SMALLINT',
+		'MEDIUMINT',
+		'INT',
+		'INTEGER',
+		'BIGINT',
+		'REAL',
+		'DOUBLE',
+		'DOUBLE PRECISION',
+		'FLOAT',
+		'DECIMAL',
+		'NUMERIC'
+	);
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
+
+		$this->_create_table .= ' DEFAULT CHARSET '.$this->db->char_set.' COLLATE '.$this->db->dbcollat;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'DROP')
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		for ($i = 0, $c = count($field); $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				$field[$i] = ($alter_type === 'ADD')
+						? "\n\tADD ".$field[$i]['_literal']
+						: "\n\tMODIFY ".$field[$i]['_literal'];
+			}
+			else
+			{
+				if ($alter_type === 'ADD')
+				{
+					$field[$i]['_literal'] = "\n\tADD ";
+				}
+				else
+				{
+					$field[$i]['_literal'] = empty($field[$i]['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
+				}
+
+				$field[$i] = $field[$i]['_literal'].$this->_process_column($field[$i]);
+			}
+		}
+
+		return array($sql.implode(',', $field));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		$extra_clause = isset($field['after'])
+			? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';
+
+		if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
+		{
+			$extra_clause = ' FIRST';
+		}
+
+		return $this->db->escape_identifiers($field['name'])
+			.(empty($field['new_name']) ? '' : $this->db->escape_identifiers($field['new_name']))
+			.' '.$field['type'].$field['length']
+			.$field['unsigned']
+			.$field['null']
+			.$field['default']
+			.$field['auto_increment']
+			.$field['unique']
+			.$extra_clause;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process indexes
+	 *
+	 * @param	string	$table	(ignored)
+	 * @return	string
+	 */
+	protected function _process_indexes($table = NULL)
+	{
+		$sql = '';
+
+		for ($i = 0, $c = count($this->keys); $i < $c; $i++)
+		{
+			if ( ! isset($this->fields[$this->keys[$i]]))
+			{
+				unset($this->keys[$i]);
+				continue;
+			}
+
+			is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);
+
+			$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
+				.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
+		}
+
+		$this->keys = array();
+
+		return $sql;
+	}
+
+}
+
+/* End of file pdo_mysql_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_mysql_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
index b03218fad..e1beb3683 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO Oracle Database Adapter Class
@@ -40,24 +41,49 @@
  */
 class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'oci';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * List of reserved identifiers
+	 *
+	 * Identifiers that must NOT be escaped.
+	 *
+	 * @var	string[]
+	 */
+	protected $_reserved_identifiers = array('*', 'rownum');
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_count_string = 'SELECT COUNT(1) AS ';
 	protected $_random_keyword = ' ASC'; // Currently not supported
 
-	protected $_reserved_identifiers = array('*', 'rownum');
+	/**
+	 * COUNT string
+	 *
+	 * @used-by	CI_DB_driver::count_all()
+	 * @used-by	CI_DB_query_builder::count_all_results()
+	 *
+	 * @var	string
+	 */
+	protected $_count_string = 'SELECT COUNT(1) AS ';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -97,7 +123,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -120,7 +146,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -135,7 +161,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -146,11 +172,11 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert_batch statement
+	 * Insert batch statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return 	string
 	 */
 	protected function _insert_batch($table, $keys, $values)
@@ -173,7 +199,7 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -190,11 +216,11 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php b/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
new file mode 100644
index 000000000..8052d218f
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_forge.php
@@ -0,0 +1,133 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO Oracle Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_oci_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_database	= FALSE;
+
+	/**
+	 * DROP DATABASE statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_database	= FALSE;
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= 'CREATE TABLE IF NOT EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'DROP')
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+		elseif ($alter_type === 'CHANGE')
+		{
+			$alter_type = 'MODIFY';
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				$field[$i] = "\n\t".$field[$i]['_literal'];
+			}
+			else
+			{
+				$field[$i]['_literal'] = "\n\t".$this->_process_column($field[$i]);
+				if ($alter_type === 'MODIFY' && ! empty($field[$i]['new_name']))
+				{
+					$sqls[] = $sql.' RENAME COLUMN '.$this->db->escape_identifiers($field[$i]['name'])
+						.' '.$this->db->escape_identifiers($field[$i]['new_name']);
+				}
+			}
+		}
+
+		$sql .= ' '.$alter_type.' ';
+		$sql .= (count($field) === 1)
+				? $fields[0]
+				: '('.implode(',', $field).')';
+
+		// RENAME COLUMN must be executed after MODIFY
+		array_unshift($sqls, $sql);
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		// Not supported - sequences and triggers must be used instead
+	}
+
+}
+
+/* End of file pdo_oci_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_oci_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index d64e9fb36..f6e0e215a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO ODBC Database Adapter Class
@@ -40,29 +41,46 @@
  */
 class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'odbc';
 
-	// The character used for escaping - not used in ODBC
-	protected $_escape_char = '';
+	/**
+	 * Database schema
+	 *
+	 * @var	string
+	 */
+	public $schema = 'public';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " {escape '%s'} ";
+	// --------------------------------------------------------------------
 
-	protected $_random_keyword = ' RAND()';
+	/**
+	 * Identifier escape character
+	 *
+	 * Must be empty for ODBC.
+	 *
+	 * @var	string
+	 */
+	protected $_escape_char = '';
 
 	/**
-	 * Database schema
+	 * ESCAPE statement string
 	 *
 	 * @var	string
 	 */
-	public $schema = 'public';
+	protected $_like_escape_str = " {escape '%s'} ";
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -129,7 +147,7 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -152,7 +170,7 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -167,8 +185,8 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -185,10 +203,10 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -215,11 +233,11 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_forge.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_forge.php
new file mode 100644
index 000000000..ab4d2bf84
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_forge.php
@@ -0,0 +1,62 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO ODBC Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/database/
+ */
+class CI_DB_pdo_odbc_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		// Not supported (in most databases at least)
+	}
+
+}
+
+/* End of file pdo_odbc_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_odbc_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 93674b576..c3f5b7603 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO PostgreSQL Database Adapter Class
@@ -40,10 +41,13 @@
  */
 class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'pgsql';
 
-	protected $_random_keyword = ' RANDOM()';
-
 	/**
 	 * Database schema
 	 *
@@ -51,12 +55,23 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 */
 	public $schema = 'public';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -77,7 +92,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	/**
 	 * Insert ID
 	 *
-	 * @param	string
+	 * @param	string	$name
 	 * @return	int
 	 */
 	public function insert_id($name = NULL)
@@ -99,7 +114,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -123,7 +138,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -138,7 +153,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -153,8 +168,8 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -171,9 +186,9 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -212,7 +227,7 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -224,11 +239,11 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php
new file mode 100644
index 000000000..484c1603d
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php
@@ -0,0 +1,194 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO PostgreSQL Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_pgsql_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'INT2'		=> 'INTEGER',
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INT4'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT',
+		'INT8'		=> 'NUMERIC',
+		'BIGINT'	=> 'NUMERIC',
+		'REAL'		=> 'DOUBLE PRECISION',
+		'FLOAT'		=> 'DOUBLE PRECISION'
+	);
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
+
+		if (version_compare($this->db->version(), '9.0', '>'))
+		{
+			$this->create_table_if = 'CREATE TABLE IF NOT EXISTS';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+ 	{
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field), $sql .= $alter_type.' '; $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				return FALSE;
+			}
+
+			if (version_compare($this->db->version(), '8', '>=') && isset($field[$i]['type']))
+			{
+				$sqls[] = $sql.' TYPE '.$field[$i]['type'].$field[$i]['length'];
+			}
+
+			if ( ! empty($field[$i]['default']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' SET '.$field[$i]['default'];
+			}
+
+			if (isset($field[$i]['null']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.($field[$i]['null'] === TRUE ? ' DROP NOT NULL' : ' SET NOT NULL');
+			}
+
+			if ( ! empty($field[$i]['new_name']))
+			{
+				$sqls[] = $sql.' RENAME '.$this->db->escape_identifiers($field[$i]['name'])
+					.' TO '.$this->db->escape_identifiers($field[$i]['new_name']);
+			}
+		}
+
+		return $sqls;
+ 	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		// Reset field lenghts for data types that don't support it
+		if (isset($attributes['CONSTRAINT']) && stripos($attributes['TYPE'], 'int') !== FALSE)
+		{
+			$attributes['CONSTRAINT'] = NULL;
+		}
+
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
+		{
+			$field['type'] = ($field['type'] === 'NUMERIC')
+						? 'BIGSERIAL'
+						: 'SERIAL';
+		}
+	}
+
+}
+
+/* End of file pdo_pgsql_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_pgsql_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
index bf0363f63..b24b13e76 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlite_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO SQLite Database Adapter Class
@@ -40,21 +41,30 @@
  */
 class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'sqlite';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
 	 */
-	protected $_random_keyword = ' RANDOM()'; // Currently not supported
+	protected $_random_keyword = ' RANDOM()';
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -81,7 +91,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -104,7 +114,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -120,7 +130,7 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -133,9 +143,9 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	/**
 	 * Replace statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return 	string
 	 */
 	protected function _replace($table, $keys, $values)
@@ -150,10 +160,10 @@ class CI_DB_pdo_sqlite_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
          */
 	protected function _truncate($table)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
new file mode 100644
index 000000000..da098df31
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php
@@ -0,0 +1,229 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.1.6 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO SQLite Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_sqlite_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= 'CREATE TABLE IF NOT EXISTS';
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= 'DROP TABLE IF EXISTS';
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
+
+		if (version_compare($this->db->version(), '3.3', '<'))
+		{
+			$this->_create_table_if = FALSE;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Create database
+	 *
+	 * @param	string	$db_name	(ignored)
+	 * @return	bool
+	 */
+	public function create_database($db_name = '')
+	{
+		// In SQLite, a database is created when you connect to the database.
+		// We'll return TRUE so that an error isn't generated
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Drop database
+	 *
+	 * @param	string	$db_name	(ignored)
+	 * @return	bool
+	 */
+	public function drop_database($db_name = '')
+	{
+		// In SQLite, a database is dropped when we delete a file
+		if (@file_exists($this->db->database))
+		{
+			// We need to close the pseudo-connection first
+			$this->db->close();
+			if ( ! @unlink($this->db->database))
+			{
+				return $this->db->db_debug ? $this->db->display_error('db_unable_to_drop') : FALSE;
+			}
+			elseif ( ! empty($this->db->data_cache['db_names']))
+			{
+				$key = array_search(strtolower($this->db->database), array_map('strtolower', $this->db->data_cache['db_names']), TRUE);
+				if ($key !== FALSE)
+				{
+					unset($this->db->data_cache['db_names'][$key]);
+				}
+			}
+
+			return TRUE;
+		}
+
+		return $this->db->db_debug ? $this->db->display_error('db_unable_to_drop') : FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if ($alter_type === 'DROP' OR $alter_type === 'CHANGE')
+		{
+			// drop_column():
+			//	BEGIN TRANSACTION;
+			//	CREATE TEMPORARY TABLE t1_backup(a,b);
+			//	INSERT INTO t1_backup SELECT a,b FROM t1;
+			//	DROP TABLE t1;
+			//	CREATE TABLE t1(a,b);
+			//	INSERT INTO t1 SELECT a,b FROM t1_backup;
+			//	DROP TABLE t1_backup;
+			//	COMMIT;
+
+			return FALSE;
+		}
+
+		return parent::_alter_table($alter_type, $table, $field);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type']
+			.$field['auto_increment']
+			.$field['null']
+			.$field['unique']
+			.$field['default'];
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'ENUM':
+			case 'SET':
+				$attributes['TYPE'] = 'TEXT';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['type'] = 'INTEGER PRIMARY KEY';
+			$field['default'] = '';
+			$field['null'] = '';
+			$field['unique'] = '';
+			$field['auto_increment'] = ' AUTOINCREMENT';
+
+			$this->primary_keys = array();
+		}
+	}
+
+}
+
+/* End of file pdo_sqlite_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlite_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
index 33bd7bea5..7bb7f8806 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 3.0.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * PDO SQLSRV Database Adapter Class
@@ -40,18 +41,40 @@
  */
 class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 
+	/**
+	 * Sub-driver
+	 *
+	 * @var	string
+	 */
 	public $subdriver = 'sqlsrv';
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
 	 * Builds the DSN if not already set.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -109,9 +132,9 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool
+	 * @param	bool	$persistent
 	 * @return	object
 	 */
 	public function db_connect($persistent = FALSE)
@@ -144,7 +167,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -169,7 +192,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -186,8 +209,8 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
          */
 	protected function _update($table, $values)
@@ -204,7 +227,7 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -220,11 +243,11 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
@@ -273,6 +296,29 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Insert batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string|bool
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		// Multiple-value inserts are only supported as of SQL Server 2008
+		if (version_compare($this->version(), '10', '>='))
+		{
+			return parent::_insert_batch($table, $keys, $values);
+		}
+
+		return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+	}
+
 }
 
 /* End of file pdo_sqlsrv_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php
new file mode 100644
index 000000000..e4b669f6e
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php
@@ -0,0 +1,136 @@
+<?php
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 2.1.0
+ * @filesource
+ */
+defined('BASEPATH') OR exit('No direct script access allowed');
+
+/**
+ * PDO SQLSRV Forge Class
+ *
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_sqlsrv_forge extends CI_DB_pdo_forge {
+
+	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";
+
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT'	=> 'SMALLINT',
+		'SMALLINT'	=> 'INT',
+		'INT'		=> 'BIGINT',
+		'REAL'		=> 'FLOAT'
+	);
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('ADD', 'DROP'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' ALTER COLUMN ';
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
+		{
+			$sqls[] = $sql.$this->_process_column($field[$i]);
+		}
+
+		return $sqls;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
+		{
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INTEGER':
+				$attributes['TYPE'] = 'INT';
+				return;
+			default: return;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['auto_increment'] = ' IDENTITY(1,1)';
+		}
+	}
+
+}
+
+/* End of file pdo_sqlsrv_forge.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlsrv_forge.php */
\ No newline at end of file
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index ca231f6f7..40f21b1e8 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Postgre Database Adapter Class
@@ -40,12 +41,13 @@
  */
 class CI_DB_postgre_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'postgre';
 
-	protected $_escape_char = '"';
-
-	protected $_random_keyword = ' RANDOM()'; // database specific random keyword
-
 	/**
 	 * Database schema
 	 *
@@ -53,8 +55,19 @@ class CI_DB_postgre_driver extends CI_DB {
 	 */
 	public $schema = 'public';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Constructor
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
+	protected $_random_keyword = ' RANDOM()'; // database specific random keyword
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
 	 *
 	 * Creates a DSN string to be used for db_connect() and db_pconnect()
 	 *
@@ -170,7 +183,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	/**
 	 * Set client character set
 	 *
-	 * @param	string
+	 * @param	string	$charset
 	 * @return	bool
 	 */
 	protected function _db_set_charset($charset)
@@ -191,8 +204,12 @@ class CI_DB_postgre_driver extends CI_DB {
 		{
 			return $this->data_cache['version'];
 		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
 
-		if (($pg_version = pg_version($this->conn_id)) === FALSE)
+		if ( ! $this->conn_id OR ($pg_version = pg_version($this->conn_id)) === FALSE)
 		{
 			return FALSE;
 		}
@@ -212,7 +229,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -225,7 +242,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -285,8 +302,8 @@ class CI_DB_postgre_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -322,7 +339,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 * Escapes data based on type
 	 * Sets boolean and null types
 	 *
-	 * @param	string
+	 * @param	string	$str
 	 * @return	mixed
 	 */
 	public function escape($str)
@@ -400,7 +417,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool	$prefix_limit = FALSE
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -424,7 +441,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -439,7 +456,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -469,8 +486,8 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -487,9 +504,9 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific batch update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
-	 * @param	string	the where key
+	 * @param	string	$table	Table name
+	 * @param	array	$values	Update data
+	 * @param	string	$index	WHERE key
 	 * @return	string
 	 */
 	protected function _update_batch($table, $values, $index)
@@ -528,7 +545,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -540,11 +557,11 @@ class CI_DB_postgre_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
diff --git a/system/database/drivers/postgre/postgre_forge.php b/system/database/drivers/postgre/postgre_forge.php
index 1164d9bb3..425622fac 100644
--- a/system/database/drivers/postgre/postgre_forge.php
+++ b/system/database/drivers/postgre/postgre_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Postgre Forge Class
@@ -34,182 +35,151 @@
  */
 class CI_DB_postgre_forge extends CI_DB_forge {
 
-	protected $_drop_table	= 'DROP TABLE IF EXISTS %s CASCADE';
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'INT2'		=> 'INTEGER',
+		'SMALLINT'	=> 'INTEGER',
+		'INT'		=> 'BIGINT',
+		'INT4'		=> 'BIGINT',
+		'INTEGER'	=> 'BIGINT',
+		'INT8'		=> 'NUMERIC',
+		'BIGINT'	=> 'NUMERIC',
+		'REAL'		=> 'DOUBLE PRECISION',
+		'FLOAT'		=> 'DOUBLE PRECISION'
+	);
 
 	/**
-	 * Process Fields
+	 * NULL value representation in CREATE/ALTER TABLE statements
 	 *
-	 * @param	mixed	$fields
-	 * @param	array	$primary_keys = array()
-	 * @return	string
+	 * @var	string
 	 */
-	protected function _process_fields($fields, $primary_keys = array())
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
 	{
-		$sql = '';
-		$current_field_count = 0;
+		parent::__construct($db);
 
-		foreach ($fields as $field => $attributes)
+		if (version_compare($this->db->version(), '9.0', '>'))
 		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
+			$this->create_table_if = 'CREATE TABLE IF NOT EXISTS';
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+ 	{
+		if (in_array($alter_type, array('DROP', 'ADD'), TRUE))
+		{
+			return parent::_alter_table($alter_type, $table, $field);
+		}
+
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
+		$sqls = array();
+		for ($i = 0, $c = count($field), $sql .= $alter_type.' '; $i < $c; $i++)
+		{
+			if ($field[$i]['_literal'] !== FALSE)
+			{
+				return FALSE;
+			}
+
+			if (version_compare($this->db->version(), '8', '>=') && isset($field[$i]['type']))
 			{
-				$sql .= "\n\t".$attributes;
+				$sqls[] = $sql.' TYPE '.$field[$i]['type'].$field[$i]['length'];
 			}
-			else
+
+			if ( ! empty($field[$i]['default']))
+			{
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.' SET '.$field[$i]['default'];
+			}
+
+			if (isset($field[$i]['null']))
 			{
-				$sql .= "\n\t".$this->db->escape_identifiers($field);
-
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-				$is_unsigned = ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE);
-
-				// Convert datatypes to be PostgreSQL-compatible
-				switch (strtoupper($attributes['TYPE']))
-				{
-					case 'TINYINT':
-						$attributes['TYPE'] = 'SMALLINT';
-						break;
-					case 'SMALLINT':
-						$attributes['TYPE'] = ($is_unsigned) ? 'INTEGER' : 'SMALLINT';
-						break;
-					case 'MEDIUMINT':
-						$attributes['TYPE'] = 'INTEGER';
-						break;
-					case 'INT':
-						$attributes['TYPE'] = ($is_unsigned) ? 'BIGINT' : 'INTEGER';
-						break;
-					case 'BIGINT':
-						$attributes['TYPE'] = ($is_unsigned) ? 'NUMERIC' : 'BIGINT';
-						break;
-					case 'DOUBLE':
-						$attributes['TYPE'] = 'DOUBLE PRECISION';
-						break;
-					case 'DATETIME':
-						$attributes['TYPE'] = 'TIMESTAMP';
-						break;
-					case 'LONGTEXT':
-						$attributes['TYPE'] = 'TEXT';
-						break;
-					case 'BLOB':
-						$attributes['TYPE'] = 'BYTEA';
-						break;
-					default:
-						break;
-				}
-
-				// If this is an auto-incrementing primary key, use the serial data type instead
-				$sql .= (in_array($field, $primary_keys) && ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-					? ' SERIAL' : ' '.$attributes['TYPE'];
-
-				// Modified to prevent constraints with integer data types
-				if ( ! empty($attributes['CONSTRAINT']) && strpos($attributes['TYPE'], 'INT') === FALSE)
-				{
-					$sql .= '('.$attributes['CONSTRAINT'].')';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
-
-				// Added new attribute to create unique fields. Also works with MySQL
-				if ( ! empty($attributes['UNIQUE']) && $attributes['UNIQUE'] === TRUE)
-				{
-					$sql .= ' UNIQUE';
-				}
+				$sqls[] = $sql.' ALTER '.$this->db->escape_identifiers($field[$i]['name'])
+					.($field[$i]['null'] === TRUE ? ' DROP NOT NULL' : ' SET NOT NULL');
 			}
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
+			if ( ! empty($field[$i]['new_name']))
 			{
-				$sql .= ',';
+				$sqls[] = $sql.' RENAME '.$this->db->escape_identifiers($field[$i]['name'])
+					.' TO '.$this->db->escape_identifiers($field[$i]['new_name']);
 			}
 		}
 
-		return $sql;
-	}
+		return $sqls;
+ 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @param	array	&$attributes
+	 * @return	void
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _attr_type(&$attributes)
 	{
-		$sql = 'CREATE TABLE ';
-
-		// PostgreSQL doesn't support IF NOT EXISTS syntax so we check if table exists manually
-		if ($if_not_exists === TRUE && $this->db->table_exists($table))
+		// Reset field lenghts for data types that don't support it
+		if (isset($attributes['CONSTRAINT']) && stripos($attributes['TYPE'], 'int') !== FALSE)
 		{
-			return TRUE;
+			$attributes['CONSTRAINT'] = NULL;
 		}
 
-		$sql .= $this->db->escape_identifiers($table).' ('.$this->_process_fields($fields, $primary_keys);
-
-		if (count($primary_keys) > 0)
+		switch (strtoupper($attributes['TYPE']))
 		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
+			case 'TINYINT':
+				$attributes['TYPE'] = 'SMALLINT';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			default: return;
 		}
-
-		$sql .= "\n);";
-
-		if (is_array($keys) && count($keys) > 0)
-		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				foreach ($key as $field)
-				{
-					$sql .= "\nCREATE INDEX ".$this->db->escape_identifiers($table.'_'.str_replace(array('"', "'"), '', $field).'_index')
-						.' ON '.$this->db->escape_identifiers($table).' ('.$this->db->escape_identifiers($field).');';
-				}
-			}
-		}
-
-		return $sql;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute AUTO_INCREMENT
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
-	 *
-	 * @param	string	$alter_type	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	$table		the table name
-	 * @param	string	$fields		the column definition
-	 * @param	string	$after_field = ''
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $fields, $after_field = '')
- 	{
- 		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' ';
-
- 		// DROP has everything it needs now.
- 		if ($alter_type === 'DROP')
- 		{
- 			return $sql.$this->db->escape_identifiers($fields);
- 		}
-
- 		return $sql.$this->_process_fields($fields)
-			.($after_field !== '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
- 	}
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
+		{
+			$field['type'] = ($field['type'] === 'NUMERIC')
+						? 'BIGSERIAL'
+						: 'SERIAL';
+		}
+	}
 
 }
 
diff --git a/system/database/drivers/postgre/postgre_result.php b/system/database/drivers/postgre/postgre_result.php
index 458ae869c..3f73f84c7 100644
--- a/system/database/drivers/postgre/postgre_result.php
+++ b/system/database/drivers/postgre/postgre_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Postgres Result Class
@@ -129,9 +130,9 @@ class CI_DB_postgre_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -160,7 +161,7 @@ class CI_DB_postgre_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/postgre/postgre_utility.php b/system/database/drivers/postgre/postgre_utility.php
index c95e6df0c..d3b2b9cdc 100644
--- a/system/database/drivers/postgre/postgre_utility.php
+++ b/system/database/drivers/postgre/postgre_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Postgre Utility Class
@@ -34,19 +35,32 @@
  */
 class CI_DB_postgre_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'SELECT datname FROM pg_database';
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= 'REINDEX TABLE %s';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Postgre Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 }
 
diff --git a/system/database/drivers/sqlite/sqlite_driver.php b/system/database/drivers/sqlite/sqlite_driver.php
index 2fd39346f..85411735c 100644
--- a/system/database/drivers/sqlite/sqlite_driver.php
+++ b/system/database/drivers/sqlite/sqlite_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite Database Adapter Class
@@ -40,13 +41,24 @@
  */
 class CI_DB_sqlite_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'sqlite';
 
-	// The character used to escape with - not needed for SQLite
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
 
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' Random()'; // database specific random keyword
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Non-persistent database connection
 	 *
@@ -112,7 +124,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -127,7 +139,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -190,8 +202,8 @@ class CI_DB_sqlite_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -250,7 +262,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -272,7 +284,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	bool
 	 */
 	protected function _list_columns($table = '')
@@ -288,7 +300,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -320,9 +332,9 @@ class CI_DB_sqlite_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific replace string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return	string
 	 */
 	protected function _replace($table, $keys, $values)
@@ -337,10 +349,10 @@ class CI_DB_sqlite_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this function maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/sqlite/sqlite_forge.php b/system/database/drivers/sqlite/sqlite_forge.php
index e02e327f3..6ad583560 100644
--- a/system/database/drivers/sqlite/sqlite_forge.php
+++ b/system/database/drivers/sqlite/sqlite_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite Forge Class
@@ -35,9 +36,32 @@
 class CI_DB_sqlite_forge extends CI_DB_forge {
 
 	/**
+	 * CREATE TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_create_table_if	= FALSE;
+
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Create database
 	 *
-	 * @param	string	the database name
+	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
 	public function create_database($db_name = '')
@@ -52,7 +76,7 @@ class CI_DB_sqlite_forge extends CI_DB_forge {
 	/**
 	 * Drop database
 	 *
-	 * @param	string	the database name (ignored)
+	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
 	public function drop_database($db_name = '')
@@ -76,126 +100,95 @@ class CI_DB_sqlite_forge extends CI_DB_forge {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * ALTER TABLE
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @todo	implement drop_column(), modify_column()
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _alter_table($alter_type, $table, $field)
 	{
-		$sql = 'CREATE TABLE ';
-
-		// IF NOT EXISTS added to SQLite in 3.3.0
-		if ($if_not_exists === TRUE && version_compare($this->db->version(), '3.3.0', '>=') === TRUE)
+		if ($alter_type === 'DROP' OR $alter_type === 'CHANGE')
 		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' (';
-		$current_field_count = 0;
-
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				empty($attributes['CONSTRAINT']) OR $sql .= '('.$attributes['CONSTRAINT'].')';
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
-
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
+			// drop_column():
+			//	BEGIN TRANSACTION;
+			//	CREATE TEMPORARY TABLE t1_backup(a,b);
+			//	INSERT INTO t1_backup SELECT a,b FROM t1;
+			//	DROP TABLE t1;
+			//	CREATE TABLE t1(a,b);
+			//	INSERT INTO t1 SELECT a,b FROM t1_backup;
+			//	DROP TABLE t1_backup;
+			//	COMMIT;
 
+			return FALSE;
+		}
 
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+		return parent::_alter_table($alter_type, $table, $field);
+	}
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	// --------------------------------------------------------------------
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type']
+			.$field['auto_increment']
+			.$field['null']
+			.$field['unique']
+			.$field['default'];
+	}
 
-		if (count($primary_keys) > 0)
-		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
-		}
+	// --------------------------------------------------------------------
 
-		if (is_array($keys) && count($keys) > 0)
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
 		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tUNIQUE (".implode(', ', $key).')';
-			}
+			case 'ENUM':
+			case 'SET':
+				$attributes['TYPE'] = 'TEXT';
+				return;
+			default: return;
 		}
-
-		return $sql."\n)";
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute AUTO_INCREMENT
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
-	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_auto_increment(&$attributes, &$field)
 	{
-		/* SQLite only supports adding new columns and it does
-		 * NOT support the AFTER statement. Each new column will
-		 * be added as the last one in the table.
-		 */
-		if ($alter_type !== 'ADD COLUMN')
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
 		{
-			// Not supported
-			return FALSE;
-		}
+			$field['type'] = 'INTEGER PRIMARY KEY';
+			$field['default'] = '';
+			$field['null'] = '';
+			$field['unique'] = '';
+			$field['auto_increment'] = ' AUTOINCREMENT';
 
-		return 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name)
-			.' '.$column_definition
-			.($default_value != '' ? " DEFAULT '".$default_value."'" : '')
-			// If NOT NULL is specified, the field must have a DEFAULT value other than NULL
-			.(($null !== NULL && $default_value !== 'NULL') ? ' NOT NULL' : ' NULL');
+			$this->primary_keys = array();
+		}
 	}
 
 }
diff --git a/system/database/drivers/sqlite/sqlite_result.php b/system/database/drivers/sqlite/sqlite_result.php
index 214841412..0e6335f73 100644
--- a/system/database/drivers/sqlite/sqlite_result.php
+++ b/system/database/drivers/sqlite/sqlite_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite Result Class
@@ -113,9 +114,9 @@ class CI_DB_sqlite_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -144,7 +145,7 @@ class CI_DB_sqlite_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/sqlite/sqlite_utility.php b/system/database/drivers/sqlite/sqlite_utility.php
index 1bcb42d9f..222d02712 100644
--- a/system/database/drivers/sqlite/sqlite_utility.php
+++ b/system/database/drivers/sqlite/sqlite_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite Utility Class
@@ -34,18 +35,16 @@
  */
 class CI_DB_sqlite_utility extends CI_DB_utility {
 
-	protected $_list_databases	= FALSE;
-
 	/**
-	 * SQLite Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/sqlite3/sqlite3_driver.php b/system/database/drivers/sqlite3/sqlite3_driver.php
index 22c72b9b8..9a2c1eefc 100644
--- a/system/database/drivers/sqlite3/sqlite3_driver.php
+++ b/system/database/drivers/sqlite3/sqlite3_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite3 Database Adapter Class
@@ -41,13 +42,24 @@
  */
 class CI_DB_sqlite3_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'sqlite3';
 
-	// The character used for escaping
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
 
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' RANDOM()';
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Non-persistent database connection
 	 *
@@ -119,7 +131,7 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -179,8 +191,8 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -239,7 +251,7 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @param	bool
+	 * @param	bool	$prefix_limit
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
@@ -257,7 +269,7 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -273,7 +285,7 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -303,9 +315,9 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific replace string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
 	 * @return	string
 	 */
 	protected function _replace($table, $keys, $values)
@@ -320,10 +332,10 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command, then,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
diff --git a/system/database/drivers/sqlite3/sqlite3_forge.php b/system/database/drivers/sqlite3/sqlite3_forge.php
index f9ae5bcce..e9b91e972 100644
--- a/system/database/drivers/sqlite3/sqlite3_forge.php
+++ b/system/database/drivers/sqlite3/sqlite3_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite3 Forge Class
@@ -35,9 +36,43 @@
 class CI_DB_sqlite3_forge extends CI_DB_forge {
 
 	/**
+	 * UNSIGNED support
+	 *
+	 * @var	bool|array
+	 */
+	protected $_unsigned		= FALSE;
+
+	/**
+	 * NULL value representation in CREATE/ALTER TABLE statements
+	 *
+	 * @var	string
+	 */
+	protected $_null		= 'NULL';
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Class constructor
+	 *
+	 * @param	object	&$db	Database object
+	 * @return	void
+	 */
+	public function __construct(&$db)
+	{
+		parent::__construct($db);
+
+		if (version_compare($this->db->version(), '3.3', '<'))
+		{
+			$this->create_table_if = FALSE;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Create database
 	 *
-	 * @param	string	the database name
+	 * @param	string	$db_name
 	 * @return	bool
 	 */
 	public function create_database($db_name = '')
@@ -52,7 +87,7 @@ class CI_DB_sqlite3_forge extends CI_DB_forge {
 	/**
 	 * Drop database
 	 *
-	 * @param	string	the database name (ignored)
+	 * @param	string	$db_name	(ignored)
 	 * @return	bool
 	 */
 	public function drop_database($db_name = '')
@@ -84,125 +119,95 @@ class CI_DB_sqlite3_forge extends CI_DB_forge {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Create Table
+	 * ALTER TABLE
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	bool
+	 * @todo	implement drop_column(), modify_column()
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	protected function _alter_table($alter_type, $table, $field)
 	{
-		$sql = 'CREATE TABLE ';
-
-		// IF NOT EXISTS added to SQLite in 3.3.0
-		if ($if_not_exists === TRUE && version_compare($this->db->version(), '3.3.0', '>=') === TRUE)
-		{
-			$sql .= 'IF NOT EXISTS ';
-		}
-
-		$sql .= $this->db->escape_identifiers($table).' (';
-		$current_field_count = 0;
-
-		foreach ($fields as $field => $attributes)
+		if ($alter_type === 'DROP' OR $alter_type === 'CHANGE')
 		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				empty($attributes['CONSTRAINT']) OR $sql .= '('.$attributes['CONSTRAINT'].')';
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
+			// drop_column():
+			//	BEGIN TRANSACTION;
+			//	CREATE TEMPORARY TABLE t1_backup(a,b);
+			//	INSERT INTO t1_backup SELECT a,b FROM t1;
+			//	DROP TABLE t1;
+			//	CREATE TABLE t1(a,b);
+			//	INSERT INTO t1 SELECT a,b FROM t1_backup;
+			//	DROP TABLE t1_backup;
+			//	COMMIT;
 
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
+			return FALSE;
+		}
 
-				$sql .= ( ! empty($attributes['NULL']) && $attributes['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+		return parent::_alter_table($alter_type, $table, $field);
+	}
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	// --------------------------------------------------------------------
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	/**
+	 * Process column
+	 *
+	 * @param	array	$field
+	 * @return	string
+	 */
+	protected function _process_column($field)
+	{
+		return $this->db->escape_identifiers($field['name'])
+			.' '.$field['type']
+			.$field['auto_increment']
+			.$field['null']
+			.$field['unique']
+			.$field['default'];
+	}
 
-		if (count($primary_keys) > 0)
-		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
-		}
+	// --------------------------------------------------------------------
 
-		if (is_array($keys) && count($keys) > 0)
+	/**
+	 * Field attribute TYPE
+	 *
+	 * Performs a data type mapping between different databases.
+	 *
+	 * @param	array	&$attributes
+	 * @return	void
+	 */
+	protected function _attr_type(&$attributes)
+	{
+		switch (strtoupper($attributes['TYPE']))
 		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->db->escape_identifiers($key));
-
-				$sql .= ",\n\tUNIQUE (".implode(', ', $key).')';
-			}
+			case 'ENUM':
+			case 'SET':
+				$attributes['TYPE'] = 'TEXT';
+				return;
+			default: return;
 		}
-
-		return $sql."\n)";
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
-	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Field attribute AUTO_INCREMENT
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_auto_increment(&$attributes, &$field)
 	{
-		/* SQLite only supports adding new columns and it does
-		 * NOT support the AFTER statement. Each new column will
-		 * be added as the last one in the table.
-		 */
-		if ($alter_type !== 'ADD COLUMN')
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
 		{
-			// Not supported
-			return FALSE;
-		}
+			$field['type'] = 'INTEGER PRIMARY KEY';
+			$field['default'] = '';
+			$field['null'] = '';
+			$field['unique'] = '';
+			$field['auto_increment'] = ' AUTOINCREMENT';
 
-		return 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name)
-			.' '.$column_definition
-			.($default_value !== '' ? ' DEFAULT '.$default_value : '')
-			// If NOT NULL is specified, the field must have a DEFAULT value other than NULL
-			.(($null !== NULL && $default_value !== 'NULL') ? ' NOT NULL' : ' NULL');
+			$this->primary_keys = array();
+		}
 	}
 
 }
diff --git a/system/database/drivers/sqlite3/sqlite3_result.php b/system/database/drivers/sqlite3/sqlite3_result.php
index 35aecda36..153e3480a 100644
--- a/system/database/drivers/sqlite3/sqlite3_result.php
+++ b/system/database/drivers/sqlite3/sqlite3_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite3 Result Class
@@ -37,9 +38,6 @@
  */
 class CI_DB_sqlite3_result extends CI_DB_result {
 
-	// num_fields() might be called multiple times, so we'll use this one to cache it's result
-	protected $_num_fields;
-
 	/**
 	 * Number of fields in the result set
 	 *
@@ -47,9 +45,7 @@ class CI_DB_sqlite3_result extends CI_DB_result {
 	 */
 	public function num_fields()
 	{
-		return ( ! is_int($this->_num_fields))
-			? $this->_num_fields = $this->result_id->numColumns()
-			: $this->_num_fields;
+		return $this->result_id->numColumns();
 	}
 
 	// --------------------------------------------------------------------
@@ -134,7 +130,7 @@ class CI_DB_sqlite3_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
@@ -165,9 +161,9 @@ class CI_DB_sqlite3_result extends CI_DB_result {
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	$n = 0	(ignored)
+	 * @param	int	$n	(ignored)
 	 * @return	array
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/sqlite3/sqlite3_utility.php b/system/database/drivers/sqlite3/sqlite3_utility.php
index f58c3d168..c7736cc6d 100644
--- a/system/database/drivers/sqlite3/sqlite3_utility.php
+++ b/system/database/drivers/sqlite3/sqlite3_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLite3 Utility Class
@@ -34,18 +35,16 @@
  */
 class CI_DB_sqlite3_utility extends CI_DB_utility {
 
-	protected $_list_databases	= FALSE;
-
 	/**
-	 * SQLite Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())
 	{
 		// Not supported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index 32f1a59d6..09ccc0200 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.0.3
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLSRV Database Adapter Class
@@ -40,20 +41,38 @@
  */
 class CI_DB_sqlsrv_driver extends CI_DB {
 
+	/**
+	 * Database driver
+	 *
+	 * @var	string
+	 */
 	public $dbdriver = 'sqlsrv';
 
-	// The character used for escaping
-	protected $_escape_char = '"';
+	// --------------------------------------------------------------------
 
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	string
+	 */
 	protected $_random_keyword = ' NEWID()';
 
-	// SQLSRV-specific properties
+	/**
+	 * Quoted identifier flag
+	 *
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
+	 */
 	protected $_quoted_identifier = TRUE;
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * Non-persistent database connection
+	 * Database connection
 	 *
-	 * @param	bool	$pooling = FALSE
+	 * @param	bool	$pooling
 	 * @return	resource
 	 */
 	public function db_connect($pooling = FALSE)
@@ -106,7 +125,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Select the database
 	 *
-	 * @param	string	database name
+	 * @param	string	$database
 	 * @return	bool
 	 */
 	public function db_select($database = '')
@@ -130,7 +149,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @param	string	$sql	an SQL query
 	 * @return	resource
 	 */
 	protected function _execute($sql)
@@ -145,7 +164,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode = FALSE
+	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -205,8 +224,8 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Escape String
 	 *
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
+	 * @param	string	$str
+	 * @param	bool	$like	Whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
@@ -256,8 +275,12 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 		{
 			return $this->data_cache['version'];
 		}
+		elseif ( ! $this->conn_id)
+		{
+			$this->initialize();
+		}
 
-		if (($info = sqlsrv_server_info($this->conn_id)) === FALSE)
+		if ( ! $this->conn_id OR ($info = sqlsrv_server_info($this->conn_id)) === FALSE)
 		{
 			return FALSE;
 		}
@@ -273,7 +296,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
 	 * @param	bool
-	 * @return	string
+	 * @return	string	$prefix_limit
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
 	{
@@ -297,7 +320,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
@@ -312,7 +335,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _field_data($table)
@@ -365,8 +388,8 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	string	the table name
-	 * @param	array	the update data
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
 	protected function _update($table, $values)
@@ -383,10 +406,10 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * If the database does not support the truncate() command,
+	 * If the database does not support the TRUNCATE statement,
 	 * then this method maps to 'DELETE FROM table'
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _truncate($table)
@@ -401,7 +424,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
 	protected function _delete($table)
@@ -417,11 +440,11 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * LIMIT
 	 *
 	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @param	string	the sql query string
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
 	protected function _limit($sql)
@@ -473,6 +496,29 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * Insert batch statement
+	 *
+	 * Generates a platform-specific insert string from the supplied data.
+	 *
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string|bool
+	 */
+	protected function _insert_batch($table, $keys, $values)
+	{
+		// Multiple-value inserts are only supported as of SQL Server 2008
+		if (version_compare($this->version(), '10', '>='))
+		{
+			return parent::_insert_batch($table, $keys, $values);
+		}
+
+		return ($this->db->db_debug) ? $this->db->display_error('db_unsupported_feature') : FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/sqlsrv/sqlsrv_forge.php b/system/database/drivers/sqlsrv/sqlsrv_forge.php
index ccdb36929..da8f68c56 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_forge.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_forge.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.0.3
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLSRV Forge Class
@@ -34,124 +35,99 @@
  */
 class CI_DB_sqlsrv_forge extends CI_DB_forge {
 
-	protected $_drop_table	= 'DROP TABLE %s';
-
 	/**
-	 * Create Table
+	 * CREATE TABLE IF statement
 	 *
-	 * @param	string	the table name
-	 * @param	array	the fields
-	 * @param	mixed	primary key(s)
-	 * @param	mixed	key(s)
-	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
-	 * @return	string
+	 * @var	string
 	 */
-	protected function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
-	{
-		$sql = ($if_not_exists === TRUE)
-			? "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'".$table."') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\n"
-			: '';
-
-		$sql .= 'CREATE TABLE '.$this->db->escape_identifiers($table).' (';
-
-		$current_field_count = 0;
-		foreach ($fields as $field => $attributes)
-		{
-			// Numeric field names aren't allowed in databases, so if the key is
-			// numeric, we know it was assigned by PHP and the developer manually
-			// entered the field information, so we'll simply add it to the list
-			if (is_numeric($field))
-			{
-				$sql .= "\n\t".$attributes;
-			}
-			else
-			{
-				$attributes = array_change_key_case($attributes, CASE_UPPER);
-
-				$sql .= "\n\t".$this->db->escape_identifiers($field).' '.$attributes['TYPE'];
-
-				if (stripos($attributes['TYPE'], 'INT') === FALSE && ! empty($attributes['CONSTRAINT']))
-				{
-					$sql .= '('.$attributes['CONSTRAINT'].')';
-				}
-
-				if ( ! empty($attributes['UNSIGNED']) && $attributes['UNSIGNED'] === TRUE)
-				{
-					$sql .= ' UNSIGNED';
-				}
+	protected $_create_table_if	= "IF NOT EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nCREATE TABLE";
 
-				if (isset($attributes['DEFAULT']))
-				{
-					$sql .= " DEFAULT '".$attributes['DEFAULT']."'";
-				}
-
-				$sql .= ( ! empty($attributes['NULL']) && $attribues['NULL'] === TRUE)
-					? ' NULL' : ' NOT NULL';
+	/**
+	 * DROP TABLE IF statement
+	 *
+	 * @var	string
+	 */
+	protected $_drop_table_if	= "IF EXISTS (SELECT * FROM sysobjects WHERE ID = object_id(N'%s') AND OBJECTPROPERTY(id, N'IsUserTable') = 1)\nDROP TABLE";
 
-				if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE)
-				{
-					$sql .= ' AUTO_INCREMENT';
-				}
-			}
+	/**
+	 * UNSIGNED support
+	 *
+	 * @var	array
+	 */
+	protected $_unsigned		= array(
+		'TINYINT'	=> 'SMALLINT',
+		'SMALLINT'	=> 'INT',
+		'INT'		=> 'BIGINT',
+		'REAL'		=> 'FLOAT'
+	);
 
-			// don't add a comma on the end of the last field
-			if (++$current_field_count < count($fields))
-			{
-				$sql .= ',';
-			}
-		}
+	// --------------------------------------------------------------------
 
-		if (count($primary_keys) > 0)
+	/**
+	 * ALTER TABLE
+	 *
+	 * @param	string	$alter_type	ALTER type
+	 * @param	string	$table		Table name
+	 * @param	mixed	$field		Column definition
+	 * @return	string|string[]
+	 */
+	protected function _alter_table($alter_type, $table, $field)
+	{
+		if (in_array($alter_type, array('ADD', 'DROP'), TRUE))
 		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
+			return parent::_alter_table($alter_type, $table, $field);
 		}
 
-		if (is_array($keys) && count($keys) > 0)
+		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' ALTER COLUMN ';
+		$sqls = array();
+		for ($i = 0, $c = count($field); $i < $c; $i++)
 		{
-			foreach ($keys as $key)
-			{
-				$key = is_array($key)
-					? $this->db->escape_identifiers($key)
-					: array($this->escape_identifiers($key));
-
-				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';
-			}
+			$sqls[] = $sql.$this->_process_column($field[$i]);
 		}
 
-		return $sql."\n)";
+		return $sqls;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Alter table query
+	 * Field attribute TYPE
 	 *
-	 * Generates a platform-specific query so that a table can be altered
-	 * Called by add_column(), drop_column(), and column_alter(),
+	 * Performs a data type mapping between different databases.
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
-	 * @return	string
+	 * @param	array	&$attributes
+	 * @return	void
 	 */
-	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _attr_type(&$attributes)
 	{
-		$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table).' '.$alter_type.' '.$this->db->escape_identifiers($column_name);
-
-		// DROP has everything it needs now.
-		if ($alter_type === 'DROP')
+		switch (strtoupper($attributes['TYPE']))
 		{
-			return $sql;
+			case 'MEDIUMINT':
+				$attributes['TYPE'] = 'INTEGER';
+				$attributes['UNSIGNED'] = FALSE;
+				return;
+			case 'INTEGER':
+				$attributes['TYPE'] = 'INT';
+				return;
+			default: return;
 		}
+	}
 
-		return $sql.' '.$column_definition
-			.($default_value != '' ? ' DEFAULT "'.$default_value.'"' : '')
-			.($null === NULL ? ' NULL' : ' NOT NULL')
-			.($after_field != '' ? ' AFTER '.$this->db->escape_identifiers($after_field) : '');
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field attribute AUTO_INCREMENT
+	 *
+	 * @param	array	&$attributes
+	 * @param	array	&$field
+	 * @return	void
+	 */
+	protected function _attr_auto_increment(&$attributes, &$field)
+	{
+		if ( ! empty($attributes['AUTO_INCREMENT']) && $attributes['AUTO_INCREMENT'] === TRUE && stripos($field['type'], 'int') !== FALSE)
+		{
+			$field['auto_increment'] = ' IDENTITY(1,1)';
+		}
 	}
 
 }
diff --git a/system/database/drivers/sqlsrv/sqlsrv_result.php b/system/database/drivers/sqlsrv/sqlsrv_result.php
index fb7a68647..6d24cc995 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_result.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_result.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLSRV Result Class
@@ -145,7 +146,7 @@ class CI_DB_sqlsrv_result extends CI_DB_result {
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')
diff --git a/system/database/drivers/sqlsrv/sqlsrv_utility.php b/system/database/drivers/sqlsrv/sqlsrv_utility.php
index d518cc15a..2bc7f9e03 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_utility.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_utility.php
@@ -1,4 +1,4 @@
-<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
@@ -24,6 +24,7 @@
  * @since		Version 2.0.3
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLSRV Utility Class
@@ -34,19 +35,32 @@
  */
 class CI_DB_sqlsrv_utility extends CI_DB_utility {
 
+	/**
+	 * List databases statement
+	 *
+	 * @var	string
+	 */
 	protected $_list_databases	= 'EXEC sp_helpdb'; // Can also be: EXEC sp_databases
+
+	/**
+	 * OPTIMIZE TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_optimize_table	= 'ALTER INDEX all ON %s REORGANIZE';
 
+	// --------------------------------------------------------------------
+
 	/**
-	 * SQLSRV Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	bool
 	 */
 	protected function _backup($params = array())
 	{
 		// Currently unsupported
-		return $this->db->display_error('db_unsuported_feature');
+		return $this->db->display_error('db_unsupported_feature');
 	}
 
 }