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

Conflicts:
	user_guide_src/source/changelog.rst

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

28 files changed, 2515 insertions, 333 deletions

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