Merge branch 'develop' of git://github.com/EllisLab/CodeIgniter into develop

Conflicts:
	user_guide_src/source/changelog.rst

31 files changed, 565 insertions, 897 deletions

diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index a3d0287f5..8e77d8396 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -45,15 +45,17 @@ class CI_DB_cubrid_driver extends CI_DB {
 	// The character used for escaping - no need in CUBRID
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in CUBRID
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	// CUBRID-specific properties
 	public $auto_commit = TRUE;
 
+	/**
+	 * Constructor
+	 *
+	 * @param	array	$params
+	 * @return	void
+	 */
 	public function __construct($params)
 	{
 		parent::__construct($params);
@@ -72,6 +74,8 @@ class CI_DB_cubrid_driver extends CI_DB {
 		}
 	}
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Non-persistent database connection
 	 *
@@ -182,6 +186,7 @@ class CI_DB_cubrid_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -396,10 +401,10 @@ class CI_DB_cubrid_driver extends CI_DB {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -423,9 +428,29 @@ class CI_DB_cubrid_driver extends CI_DB {
 				.'ELSE '.$k.' END, ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN ('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/cubrid/cubrid_result.php b/system/database/drivers/cubrid/cubrid_result.php
index 4a06a2d39..360c50dc2 100644
--- a/system/database/drivers/cubrid/cubrid_result.php
+++ b/system/database/drivers/cubrid/cubrid_result.php
@@ -132,6 +132,7 @@ class CI_DB_cubrid_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index c9027670d..c3be519bf 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -45,10 +45,6 @@ class CI_DB_ibase_driver extends CI_DB {
 	// The character used to escape with
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' Random()'; // database specific random keyword
 
 	// Keeps track of the resource for the current transaction
@@ -120,6 +116,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -285,7 +282,10 @@ class CI_DB_ibase_driver extends CI_DB {
 	 */
 	protected function _field_data($table)
 	{
-		return $this->_limit('SELECT * FROM '.$this->protect_identifiers($table), 1, NULL);
+		$this->qb_limit = 1;
+		$sql = $this->_limit('SELECT * FROM '.$this->protect_identifiers($table));
+		$this->qb_limit = 0;
+		return $sql;
 	}
 
 	// --------------------------------------------------------------------
@@ -306,51 +306,18 @@ class CI_DB_ibase_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This public function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
 	 */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
-			.$where
-			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '');
+		$this->qb_limit = FALSE;
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -379,19 +346,12 @@ class CI_DB_ibase_driver extends CI_DB {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -402,22 +362,20 @@ class CI_DB_ibase_driver extends CI_DB {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
 		// Limit clause depends on if Interbase or Firebird
 		if (stripos($this->version(), 'firebird') !== FALSE)
 		{
-			$select = 'FIRST '. (int) $limit
-				.($offset ? ' SKIP '. (int) $offset : '');
+			$select = 'FIRST '.$this->qb_limit
+				.($this->qb_offset ? ' SKIP '.$this->qb_offset : '');
 		}
 		else
 		{
 			$select = 'ROWS '
-				.($offset ? (int) $offset.' TO '.($limit + $offset) : (int) $limit);
+				.($this->qb_offset ? $this->qb_offset.' TO '.($this->qb_limit + $this->qb_offset) : $this->qb_limit);
 		}
 
 		return preg_replace('`SELECT`i', 'SELECT '.$select, $sql);
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 1714704a8..2063dad90 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -45,21 +45,17 @@ class CI_DB_mssql_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' NEWID()';
 
 	// MSSQL-specific properties
 	protected $_quoted_identifier = TRUE;
 
-	/*
+	/**
 	 * Constructor
 	 *
 	 * Appends the port number to the hostname, if needed.
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -156,6 +152,7 @@ class CI_DB_mssql_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -366,49 +363,19 @@ class CI_DB_mssql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
 	 */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).' WHERE '.$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -437,23 +404,16 @@ class CI_DB_mssql_driver extends CI_DB {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
+		if ($this->qb_limit)
+		{
+			return 'WITH ci_delete AS (SELECT TOP '.$this->qb_limit.' * FROM '.$table.$this->_compile_wh('qb_where').') DELETE FROM ci_delete';
+		}
 
-		return ($limit)
-			? 'WITH ci_delete AS (SELECT TOP '.$limit.' * FROM '.$table.$conditions.') DELETE FROM ci_delete'
-			: 'DELETE FROM '.$table.$conditions;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -464,33 +424,44 @@ class CI_DB_mssql_driver extends CI_DB {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		// As of SQL Server 2012 (11.0.*) OFFSET is supported
-		if (version_compare($this->version(), '11', '>='))
-		{
-			return $sql.' OFFSET '.(int) $offset.' ROWS FETCH NEXT '.(int) $limit.' ROWS ONLY';
-		}
-
-		$limit = $offset + $limit;
+		$limit = $this->qb_offset + $this->qb_limit;
 
 		// As of SQL Server 2005 (9.0.*) ROW_NUMBER() is supported,
 		// however an ORDER BY clause is required for it to work
-		if (version_compare($this->version(), '9', '>=') && $offset && ! empty($this->qb_orderby))
+		if (version_compare($this->version(), '9', '>=') && $this->qb_offset && ! empty($this->qb_orderby))
 		{
-			$orderby = 'ORDER BY '.implode(', ', $this->qb_orderby);
+			$orderby = $this->_compile_order_by();
 
 			// We have to strip the ORDER BY clause
-			$sql = trim(substr($sql, 0, strrpos($sql, 'ORDER BY '.$orderby)));
+			$sql = trim(substr($sql, 0, strrpos($sql, $orderby)));
+
+			// Get the fields to select from our subquery, so that we can avoid CI_rownum appearing in the actual results
+			if (count($this->qb_select) === 0)
+			{
+				$select = '*'; // Inevitable
+			}
+			else
+			{
+				// Use only field names and their aliases, everything else is out of our scope.
+				$select = array();
+				$field_regexp = ($this->_quoted_identifier)
+					? '("[^\"]+")' : '(\[[^\]]+\])';
+				for ($i = 0, $c = count($this->qb_select); $i < $c; $i++)
+				{
+					$select[] = preg_match('/(?:\s|\.)'.$field_regexp.'$/i', $this->qb_select[$i], $m)
+						? $m[1] : $this->qb_select[$i];
+				}
+				$select = implode(', ', $select);
+			}
 
-			return 'SELECT '.(count($this->qb_select) === 0 ? '*' : implode(', ', $this->qb_select))." FROM (\n"
-				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.$orderby.') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
-				."\n) ".$this->escape_identifiers('CI_subquery')
-				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.((int) $offset + 1).' AND '.$limit;
+			return 'SELECT '.$select." FROM (\n\n"
+				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.trim($orderby).') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
+				."\n\n) ".$this->escape_identifiers('CI_subquery')
+				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.($this->qb_offset + 1).' AND '.$limit;
 		}
 
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
diff --git a/system/database/drivers/mssql/mssql_result.php b/system/database/drivers/mssql/mssql_result.php
index aeede3f4b..84d2814f1 100644
--- a/system/database/drivers/mssql/mssql_result.php
+++ b/system/database/drivers/mssql/mssql_result.php
@@ -133,6 +133,7 @@ class CI_DB_mssql_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index 29db90408..f82e775e6 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -41,14 +41,11 @@
 class CI_DB_mysql_driver extends CI_DB {
 
 	public $dbdriver = 'mysql';
+	public $compress = FALSE;
 
 	// The character used for escaping
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	/**
@@ -79,11 +76,21 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Non-persistent database connection
 	 *
+	 * @param	bool
 	 * @return	resource
 	 */
-	public function db_connect()
+	public function db_connect($persistent = FALSE)
 	{
-		return @mysql_connect($this->hostname, $this->username, $this->password, TRUE);
+		$client_flags = ($this->compress === FALSE) ? 0 : MYSQL_CLIENT_COMPRESS;
+
+		if ($this->encrypt === TRUE)
+		{
+			$client_flags = $client_flags | MYSQL_CLIENT_SSL;
+		}
+
+		return ($persistent === TRUE)
+			? @mysql_pconnect($this->hostname, $this->username, $this->password, $client_flags)
+			: @mysql_connect($this->hostname, $this->username, $this->password, TRUE, $client_flags);
 	}
 
 	// --------------------------------------------------------------------
@@ -95,7 +102,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	 */
 	public function db_pconnect()
 	{
-		return @mysql_pconnect($this->hostname, $this->username, $this->password);
+		return $this->db_connect(TRUE);
 	}
 
 	// --------------------------------------------------------------------
@@ -207,6 +214,7 @@ class CI_DB_mysql_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -420,10 +428,10 @@ class CI_DB_mysql_driver extends CI_DB {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -447,9 +455,29 @@ class CI_DB_mysql_driver extends CI_DB {
 				.'ELSE '.$k.' END, ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/mysql/mysql_result.php b/system/database/drivers/mysql/mysql_result.php
index 7fbb65496..b3f669e40 100644
--- a/system/database/drivers/mysql/mysql_result.php
+++ b/system/database/drivers/mysql/mysql_result.php
@@ -146,6 +146,7 @@ class CI_DB_mysql_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index be61aab20..6c4f87513 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -41,14 +41,11 @@
 class CI_DB_mysqli_driver extends CI_DB {
 
 	public $dbdriver = 'mysqli';
+	public $compress = FALSE;
 
 	// The character used for escaping
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()'; // database specific random keyword
 
 	/**
@@ -61,13 +58,21 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Non-persistent database connection
 	 *
+	 * @param	bool
 	 * @return	object
+	 * @todo	SSL support
 	 */
-	public function db_connect()
+	public function db_connect($persistent = FALSE)
 	{
-		return empty($this->port)
-			? @new mysqli($this->hostname, $this->username, $this->password, $this->database)
-			: @new mysqli($this->hostname, $this->username, $this->password, $this->database, $this->port);
+		// Persistent connection support was added in PHP 5.3.0
+		$hostname = ($persistent === TRUE && is_php('5.3'))
+			? 'p:'.$this->hostname : $this->hostname;
+		$port = empty($this->port) ? NULL : $this->port;
+		$client_flags = ($this->compress === TRUE) ? MYSQLI_CLIENT_COMPRESS : 0;
+		$mysqli = mysqli_init();
+
+		return @$mysqli->real_connect($hostname, $this->username, $this->password, $this->database, $port, NULL, $client_flags)
+			? $mysqli : FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -79,15 +84,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 */
 	public function db_pconnect()
 	{
-		// Persistent connection support was added in PHP 5.3.0
-		if ( ! is_php('5.3'))
-		{
-			return $this->db_connect();
-		}
-
-		return empty($this->port)
-			? @new mysqli('p:'.$this->hostname, $this->username, $this->password, $this->database)
-			: @new mysqli('p:'.$this->hostname, $this->username, $this->password, $this->database, $this->port);
+		return $this->db_connect(TRUE);
 	}
 
 	// --------------------------------------------------------------------
@@ -199,6 +196,7 @@ class CI_DB_mysqli_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -400,6 +398,14 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 */
 	public function error()
 	{
+		if ( ! empty($this->conn_id->connect_errno))
+		{
+			return array(
+				'code' => $this->conn_id->connect_errno,
+				'message' => is_php('5.2.9') ? $this->conn_id->connect_error : mysqli_connect_error()
+			);
+		}
+
 		return array('code' => $this->conn_id->errno, 'message' => $this->conn_id->error);
 	}
 
@@ -412,10 +418,10 @@ class CI_DB_mysqli_driver extends CI_DB {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -439,11 +445,29 @@ class CI_DB_mysqli_driver extends CI_DB {
 				.'ELSE '.$k.' END, ';
 		}
 
-		$where = ($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		return implode(', ', $this->qb_from);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/mysqli/mysqli_result.php b/system/database/drivers/mysqli/mysqli_result.php
index c1ec4da76..f036302bb 100644
--- a/system/database/drivers/mysqli/mysqli_result.php
+++ b/system/database/drivers/mysqli/mysqli_result.php
@@ -132,6 +132,7 @@ class CI_DB_mysqli_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index 691247fee..81d73d073 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -54,10 +54,6 @@ class CI_DB_oci8_driver extends CI_DB {
 	// The character used for excaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	/**
 	 * The syntax to count rows is slightly different across different
 	 * database engines, so this string appears in each driver and is
@@ -79,6 +75,12 @@ class CI_DB_oci8_driver extends CI_DB {
 	// throw off num_fields later
 	public $limit_used;
 
+	/**
+	 * Constructor
+	 *
+	 * @param	array	$params
+	 * @return	void
+	 */
 	public function __construct($params)
 	{
 		parent::__construct($params);
@@ -547,22 +549,6 @@ class CI_DB_oci8_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
@@ -611,20 +597,17 @@ class CI_DB_oci8_driver extends CI_DB {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-		empty($limit) OR $conditions[] = 'rownum <= '.$limit;
+		if ($this->qb_limit)
+		{
+			$this->where('rownum <= ',$this->qb_limit, FALSE);
+			$this->qb_limit = FALSE;
+		}
 
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -635,15 +618,13 @@ class CI_DB_oci8_driver extends CI_DB {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
 		$this->limit_used = TRUE;
-		return 'SELECT * FROM (SELECT inner_query.*, rownum rnum FROM ('.$sql.') inner_query WHERE rownum < '.($offset + $limit + 1).')'
-			.($offset ? ' WHERE rnum >= '.($offset + 1): '');
+		return 'SELECT * FROM (SELECT inner_query.*, rownum rnum FROM ('.$sql.') inner_query WHERE rownum < '.($this->qb_offset + $this->qb_limit + 1).')'
+			.($this->qb_offset ? ' WHERE rnum >= '.($this->qb_offset + 1): '');
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 8f0a474b0..063a04b98 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -45,12 +45,16 @@ class CI_DB_odbc_driver extends CI_DB {
 	// the character used to excape - not necessary for ODBC
 	protected $_escape_char = '';
 
-	// clause and character used for LIKE escape sequences
 	protected $_like_escape_str = " {escape '%s'} ";
-	protected $_like_escape_chr = '!';
 
 	protected $_random_keyword;
 
+	/**
+	 * Constructor
+	 *
+	 * @param	array	$params
+	 * @return	void
+	 */
 	public function __construct($params)
 	{
 		parent::__construct($params);
@@ -64,6 +68,8 @@ class CI_DB_odbc_driver extends CI_DB {
 		}
 	}
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Non-persistent database connection
 	 *
@@ -104,6 +110,7 @@ class CI_DB_odbc_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -291,17 +298,19 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
+	 * Update statement
 	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
+	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @param	array
+	 * @param	string	the table name
+	 * @param	array	the update data
 	 * @return	string
-	 */
-	protected function _from_tables($tables)
+         */
+	protected function _update($table, $values)
 	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -325,6 +334,22 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * Delete statement
+	 *
+	 * Generates a platform-specific delete string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	protected function _delete($table)
+	{
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 705b16560..32a9e7509 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -45,10 +45,6 @@ class CI_DB_pdo_driver extends CI_DB {
 	// The character used to escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword;
 
 	public $trans_enabled = FALSE;
@@ -61,7 +57,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	 *
 	 * Validates the DSN string and/or detects the subdriver
 	 *
-	 * @param	array
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -187,6 +183,7 @@ class CI_DB_pdo_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -360,14 +357,12 @@ class CI_DB_pdo_driver extends CI_DB {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
-		$where = ($where !== '' && count($where) >=1) ? implode(' ', $where).' AND ' : '';
-
 		foreach ($values as $key => $val)
 		{
 			$ids[] = $val[$index];
@@ -381,9 +376,7 @@ class CI_DB_pdo_driver extends CI_DB {
 			}
 		}
 
-		$sql   = 'UPDATE '.$table.' SET ';
 		$cases = '';
-
 		foreach ($final as $k => $v)
 		{
 			$cases .= $k.' = CASE '."\n";
@@ -396,10 +389,9 @@ class CI_DB_pdo_driver extends CI_DB {
 			$cases .= 'ELSE '.$k.' END, ';
 		}
 
-		$sql .= substr($cases, 0, -2);
-		$sql .= ' WHERE '.$where.$index.' IN ('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
 
-		return $sql;
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
index e287f5c63..438d312a1 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
@@ -130,49 +130,19 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -183,21 +153,12 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
-
-		return 'DELETE FROM '.$table.$conditions;
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -208,13 +169,11 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		return $sql.' LIMIT '.$limit.($offset ? ' OFFSET '.$offset : '');
+		return $sql.' LIMIT '.$this->qb_limit.($this->qb_offset ? ' OFFSET '.$this->qb_offset : '');
 	}
 
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index 05eeacfe6..d2a484d9e 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -44,10 +44,6 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in CUBRID
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()';
 
 	/**
@@ -133,10 +129,10 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -160,9 +156,9 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 				.'ELSE '.$k.' END), ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
 	}
 
 	// --------------------------------------------------------------------
@@ -183,6 +179,26 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_cubrid_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index 7060c9eb9..785b2795c 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -153,49 +153,19 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -206,23 +176,16 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
+		if ($this->qb_limit)
+		{
+			return 'WITH ci_delete AS (SELECT TOP '.$this->qb_limit.' * FROM '.$table.$this->_compile_wh('qb_where').') DELETE FROM ci_delete';
+		}
 
-		return ($limit)
-			? 'WITH ci_delete AS (SELECT TOP '.$limit.' * FROM '.$table.$conditions.') DELETE FROM ci_delete'
-			: 'DELETE FROM '.$table.$conditions;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -233,27 +196,44 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		$limit = $offset + $limit;
+		$limit = $this->qb_offset + $this->qb_limit;
 
 		// As of SQL Server 2005 (9.0.*) ROW_NUMBER() is supported,
 		// however an ORDER BY clause is required for it to work
-		if (version_compare($this->version(), '9', '>=') && $offset && ! empty($this->qb_orderby))
+		if (version_compare($this->version(), '9', '>=') && $this->qb_offset && ! empty($this->qb_orderby))
 		{
-			$orderby = 'ORDER BY '.implode(', ', $this->qb_orderby);
+			$orderby = $this->_compile_order_by();
 
 			// We have to strip the ORDER BY clause
-			$sql = trim(substr($sql, 0, strrpos($sql, 'ORDER BY '.$orderby)));
+			$sql = trim(substr($sql, 0, strrpos($sql, $orderby)));
+
+			// Get the fields to select from our subquery, so that we can avoid CI_rownum appearing in the actual results
+			if (count($this->qb_select) === 0)
+			{
+				$select = '*'; // Inevitable
+			}
+			else
+			{
+				// Use only field names and their aliases, everything else is out of our scope.
+				$select = array();
+				$field_regexp = ($this->_quoted_identifier)
+					? '("[^\"]+")' : '(\[[^\]]+\])';
+				for ($i = 0, $c = count($this->qb_select); $i < $c; $i++)
+				{
+					$select[] = preg_match('/(?:\s|\.)'.$field_regexp.'$/i', $this->qb_select[$i], $m)
+						? $m[1] : $this->qb_select[$i];
+				}
+				$select = implode(', ', $select);
+			}
 
-			return 'SELECT '.(count($this->qb_select) === 0 ? '*' : implode(', ', $this->qb_select))." FROM (\n"
-				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.$orderby.') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
-				."\n) ".$this->escape_identifiers('CI_subquery')
-				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.((int) $offset + 1).' AND '.$limit;
+			return 'SELECT '.$select." FROM (\n\n"
+				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.trim($orderby).') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
+				."\n\n) ".$this->escape_identifiers('CI_subquery')
+				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.($this->qb_offset + 1).' AND '.$limit;
 		}
 
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
@@ -262,4 +242,4 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 }
 
 /* End of file pdo_dblib_driver.php */
-/* Location: ./system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_dblib_driver.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 c074a9a78..32d1f219a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -139,51 +139,18 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return 	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
 	 */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
-			.$where
-			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '');
+		$this->qb_limit = FALSE;
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -212,19 +179,12 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -235,22 +195,20 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
 		// Limit clause depends on if Interbase or Firebird
 		if (stripos($this->version(), 'firebird') !== FALSE)
 		{
-			$select = 'FIRST '. (int) $limit
-				.($offset > 0 ? ' SKIP '. (int) $offset : '');
+			$select = 'FIRST '.$this->qb_limit
+				.($this->qb_offset > 0 ? ' SKIP '.$this->qb_offset : '');
 		}
 		else
 		{
 			$select = 'ROWS '
-				.($offset > 0 ? (int) $offset.' TO '.($limit + $offset) : (int) $limit);
+				.($this->qb_offset > 0 ? $this->qb_offset.' TO '.($this->qb_limit + $this->qb_offset) : $this->qb_limit);
 		}
 
 		return preg_replace('`SELECT`i', 'SELECT '.$select, $sql);
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
index 832c03c96..22a5f928c 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
@@ -165,49 +165,19 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -218,21 +188,12 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
-
-		return 'DELETE FROM '.$table.$conditions;
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
index a3efc63dc..8dd430184 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
@@ -159,49 +159,19 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -230,21 +200,12 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
-
-		return 'DELETE FROM '.$table.$conditions;
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -255,13 +216,11 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		$select = 'SELECT '.($offset ? 'SKIP '.$offset : '').'FIRST '.$limit.' ';
+		$select = 'SELECT '.($this->qb_offset ? 'SKIP '.$this->qb_offset : '').'FIRST '.$this->qb_limit.' ';
 		return preg_replace('/^(SELECT\s)/i', $select, $sql, 1);
 	}
 
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index 78afe246c..0fb5d8f12 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -41,13 +41,10 @@
 class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 
 	public $subdriver = 'mysql';
+	public $compress = FALSE;
 
 	protected $_escape_char = '`';
 
-	// clause and character used for LIKE escape sequences - not used in MySQL
-	protected $_like_escape_str = '';
-	protected $_like_escape_chr = '\\';
-
 	protected $_random_keyword = ' RAND()';
 
 	/**
@@ -83,6 +80,7 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * @param	bool
 	 * @return	object
+	 * @todo	SSL support
 	 */
 	public function db_connect($persistent = FALSE)
 	{
@@ -97,6 +95,11 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 				.(empty($this->dbcollat) ? '' : ' COLLATE '.$this->dbcollat);
 		}
 
+		if ($this->compress === TRUE)
+		{
+			$this->options[PDO::MYSQL_ATTR_COMPRESS] = TRUE;
+		}
+
 		return parent::db_connect($persistent);
 	}
 
@@ -161,10 +164,10 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -188,9 +191,9 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 				.'ELSE '.$k.' END), ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
 	}
 
 	// --------------------------------------------------------------------
@@ -211,6 +214,26 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_mysql_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
index 56ec1bce1..b03218fad 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
@@ -146,22 +146,6 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * @param	string	the table name
@@ -190,20 +174,17 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-		empty($limit) OR $conditions[] = 'rownum <= '.$limit;
+		if ($this->qb_limit)
+		{
+			$this->where('rownum <= ',$this->qb_limit, FALSE);
+			$this->qb_limit = FALSE;
+		}
 
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -214,14 +195,12 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		return 'SELECT * FROM (SELECT inner_query.*, rownum rnum FROM ('.$sql.') inner_query WHERE rownum < '.($offset + $limit + 1).')'
-			.($offset ? ' WHERE rnum >= '.($offset + 1): '');
+		return 'SELECT * FROM (SELECT inner_query.*, rownum rnum FROM ('.$sql.') inner_query WHERE rownum < '.($this->qb_offset + $this->qb_limit + 1).')'
+			.($this->qb_offset ? ' WHERE rnum >= '.($this->qb_offset + 1): '');
 	}
 
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index 392754ff7..5944d55f4 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -46,7 +46,6 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	protected $_escape_char = '';
 
 	// clause and character used for LIKE escape sequences
-	protected $_like_escape_chr = '!';
 	protected $_like_escape_str = " {escape '%s'} ";
 
 	protected $_random_keyword = ' RAND()';
@@ -157,49 +156,19 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -228,21 +197,12 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
-
-		return 'DELETE FROM '.$table.$conditions;
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -253,13 +213,11 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
+		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$this->qb_limit.' ', $sql);
 	}
 
 }
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 9a476f143..74d56e6b8 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -142,49 +142,19 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -196,10 +166,10 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -218,14 +188,14 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 		$cases = '';
 		foreach ($final as $k => $v)
 		{
-			$cases .= $k.' = (CASE '.$k."\n"
+			$cases .= $k.' = (CASE '.$index."\n"
 				.implode("\n", $v)."\n"
 				.'ELSE '.$k.' END), ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
 	}
 
 	// --------------------------------------------------------------------
@@ -236,19 +206,12 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -259,29 +222,31 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		return $sql.' LIMIT '.$limit.($offset ? ' OFFSET '.$offset : '');
+		return $sql.' LIMIT '.$this->qb_limit.($this->qb_offset ? ' OFFSET '.$this->qb_offset : '');
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where
+	 * WHERE, HAVING
 	 *
-	 * Called by where() or or_where()
+	 * Called by where(), or_where(), having(), or_having()
 	 *
+	 * @param	string	'qb_where' or 'qb_having'
 	 * @param	mixed
 	 * @param	mixed
 	 * @param	string
+	 * @param	bool
 	 * @return	object
 	 */
-	protected function _where($key, $value = NULL, $type = 'AND ', $escape = NULL)
+	protected function _wh($qb_key, $key, $value = NULL, $type = 'AND ', $escape = NULL)
 	{
+		$qb_cache_key = ($qb_key === 'qb_having') ? 'qb_cache_having' : 'qb_cache_where';
+
 		if ( ! is_array($key))
 		{
 			$key = array($key => $value);
@@ -292,14 +257,10 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 
 		foreach ($key as $k => $v)
 		{
-			$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0)
+			$prefix = (count($this->$qb_key) === 0 && count($this->$qb_cache_key) === 0)
 				? $this->_group_get_type('')
 				: $this->_group_get_type($type);
 
-			$k = (($op = $this->_get_operator($k)) !== FALSE)
-				? $this->protect_identifiers(substr($k, 0, strpos($k, $op)), FALSE, $escape).strstr($k, $op)
-				: $this->protect_identifiers($k, FALSE, $escape);
-
 			if (is_null($v) && ! $this->_has_operator($k))
 			{
 				// value appears not to have been set, assign the test to IS NULL
@@ -308,13 +269,13 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 
 			if ( ! is_null($v))
 			{
-				if ($escape === TRUE)
+				if (is_bool($v))
 				{
-					$v = ' '.$this->escape($v);
+					$v = ' '.($v ? 'TRUE' : 'FALSE');
 				}
-				elseif (is_bool($v))
+				elseif ($escape === TRUE)
 				{
-					$v = ($v ? ' TRUE' : ' FALSE');
+					$v = ' '.(is_int($v) ? $v : $this->escape($v));
 				}
 
 				if ( ! $this->_has_operator($k))
@@ -323,11 +284,11 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 				}
 			}
 
-			$this->qb_where[] = $prefix.$k.$v;
+			$this->{$qb_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
 			if ($this->qb_caching === TRUE)
 			{
-				$this->qb_cache_where[] = $prefix.$k.$v;
-				$this->qb_cache_exists[] = 'where';
+				$this->{$qb_cache_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
+				$this->qb_cache_exists[] = substr($qb_key, 3);
 			}
 
 		}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
index f125b8f50..33bd7bea5 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
@@ -78,9 +78,9 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 				$this->dsn .= ';ConnectionPooling='.$this->ConnectionPooling;
 			}
 
-			if (isset($this->Encrypt))
+			if ($this->encrypt === TRUE)
 			{
-				$this->dsn .= ';Encrypt='.$this->Encrypt;
+				$this->dsn .= ';Encrypt=1';
 			}
 
 			if (isset($this->TraceOn))
@@ -182,49 +182,19 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
          */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -235,23 +205,16 @@ 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	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
+		if ($this->qb_limit)
+		{
+			return 'WITH ci_delete AS (SELECT TOP '.$this->qb_limit.' * FROM '.$table.$this->_compile_wh('qb_where').') DELETE FROM ci_delete';
+		}
 
-		return ($limit)
-			? 'WITH ci_delete AS (SELECT TOP '.$limit.' * FROM '.$table.$conditions.') DELETE FROM ci_delete'
-			: 'DELETE FROM '.$table.$conditions;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -262,32 +225,49 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
 		// As of SQL Server 2012 (11.0.*) OFFSET is supported
 		if (version_compare($this->version(), '11', '>='))
 		{
-			return $sql.' OFFSET '.(int) $offset.' ROWS FETCH NEXT '.(int) $limit.' ROWS ONLY';
+			return $sql.' OFFSET '.(int) $this->qb_offset.' ROWS FETCH NEXT '.$this->qb_limit.' ROWS ONLY';
 		}
 
-		$limit = $offset + $limit;
+		$limit = $this->qb_offset + $this->qb_limit;
 
 		// An ORDER BY clause is required for ROW_NUMBER() to work
-		if ($offset && ! empty($this->qb_orderby))
+		if ($this->qb_offset && ! empty($this->qb_orderby))
 		{
-			$orderby = 'ORDER BY '.implode(', ', $this->qb_orderby);
+			$orderby = $this->_compile_order_by();
 
 			// We have to strip the ORDER BY clause
-			$sql = trim(substr($sql, 0, strrpos($sql, 'ORDER BY '.$orderby)));
+			$sql = trim(substr($sql, 0, strrpos($sql, $orderby)));
+
+			// Get the fields to select from our subquery, so that we can avoid CI_rownum appearing in the actual results
+			if (count($this->qb_select) === 0)
+			{
+				$select = '*'; // Inevitable
+			}
+			else
+			{
+				// Use only field names and their aliases, everything else is out of our scope.
+				$select = array();
+				$field_regexp = ($this->_quoted_identifier)
+					? '("[^\"]+")' : '(\[[^\]]+\])';
+				for ($i = 0, $c = count($this->qb_select); $i < $c; $i++)
+				{
+					$select[] = preg_match('/(?:\s|\.)'.$field_regexp.'$/i', $this->qb_select[$i], $m)
+						? $m[1] : $this->qb_select[$i];
+				}
+				$select = implode(', ', $select);
+			}
 
-			return 'SELECT '.(count($this->qb_select) === 0 ? '*' : implode(', ', $this->qb_select))." FROM (\n"
-				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.$orderby.') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
-				."\n) ".$this->escape_identifiers('CI_subquery')
-				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.((int) $offset + 1).' AND '.$limit;
+			return 'SELECT '.$select." FROM (\n\n"
+				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.trim($orderby).') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
+				."\n\n) ".$this->escape_identifiers('CI_subquery')
+				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.($this->qb_offset + 1).' AND '.$limit;
 		}
 
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);
@@ -296,4 +276,4 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 }
 
 /* End of file pdo_sqlsrv_driver.php */
-/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php */
\ No newline at end of file
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index 031740851..1b9474920 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -44,10 +44,6 @@ class CI_DB_postgre_driver extends CI_DB {
 
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' RANDOM()'; // database specific random keyword
 
 	/**
@@ -55,6 +51,7 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * Creates a DSN string to be used for db_connect() and db_pconnect()
 	 *
+	 * @param	array	$params
 	 * @return	void
 	 */
 	public function __construct($params)
@@ -132,7 +129,15 @@ class CI_DB_postgre_driver extends CI_DB {
 	 */
 	public function db_pconnect()
 	{
-		return @pg_pconnect($this->dsn);
+		$conn = @pg_pconnect($this->dsn);
+		if ($conn && pg_connection_status($conn) === PGSQL_CONNECTION_BAD)
+		{
+			if (pg_ping($conn) === FALSE)
+			{
+				return FALSE;
+			}
+		}
+		return $conn;
 	}
 
 	// --------------------------------------------------------------------
@@ -453,49 +458,19 @@ class CI_DB_postgre_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
 	 */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -507,10 +482,10 @@ class CI_DB_postgre_driver extends CI_DB {
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
+	 * @param	string	the where key
 	 * @return	string
 	 */
-	protected function _update_batch($table, $values, $index, $where = NULL)
+	protected function _update_batch($table, $values, $index)
 	{
 		$ids = array();
 		foreach ($values as $key => $val)
@@ -534,9 +509,9 @@ class CI_DB_postgre_driver extends CI_DB {
 				.'ELSE '.$k.' END), ';
 		}
 
-		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2)
-			.' WHERE '.(($where !== '' && count($where) > 0) ? implode(' ', $where).' AND ' : '')
-			.$index.' IN('.implode(',', $ids).')';
+		$this->where($index.' IN('.implode(',', $ids).')', NULL, FALSE);
+
+		return 'UPDATE '.$table.' SET '.substr($cases, 0, -2).$this->_compile_wh('qb_where');
 	}
 
 	// --------------------------------------------------------------------
@@ -547,19 +522,12 @@ class CI_DB_postgre_driver extends CI_DB {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause (ignored)
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+		$this->qb_limit = FALSE;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -570,30 +538,31 @@ class CI_DB_postgre_driver extends CI_DB {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
-		return $sql.' LIMIT '.$limit.($offset ? ' OFFSET '.$offset : '');
+		return $sql.' LIMIT '.$this->qb_limit.($this->qb_offset ? ' OFFSET '.$this->qb_offset : '');
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Where
+	 * WHERE, HAVING
 	 *
-	 * Called by where() or or_where()
+	 * Called by where(), or_where(), having(), or_having()
 	 *
+	 * @param	string	'qb_where' or 'qb_having'
 	 * @param	mixed
 	 * @param	mixed
 	 * @param	string
-	 * @param	mixed
+	 * @param	bool
 	 * @return	object
 	 */
-	protected function _where($key, $value = NULL, $type = 'AND ', $escape = NULL)
+	protected function _wh($qb_key, $key, $value = NULL, $type = 'AND ', $escape = NULL)
 	{
+		$qb_cache_key = ($qb_key === 'qb_having') ? 'qb_cache_having' : 'qb_cache_where';
+
 		if ( ! is_array($key))
 		{
 			$key = array($key => $value);
@@ -604,17 +573,10 @@ class CI_DB_postgre_driver extends CI_DB {
 
 		foreach ($key as $k => $v)
 		{
-			$prefix = (count($this->qb_where) === 0 && count($this->qb_cache_where) === 0)
+			$prefix = (count($this->$qb_key) === 0 && count($this->$qb_cache_key) === 0)
 				? $this->_group_get_type('')
 				: $this->_group_get_type($type);
 
-			if ($escape === TRUE)
-			{
-				$k = (($op = $this->_get_operator($k)) !== FALSE)
-					? $this->escape_identifiers(trim(substr($k, 0, strpos($k, $op)))).' '.strstr($k, $op)
-					: $this->escape_identifiers(trim($k));
-			}
-
 			if (is_null($v) && ! $this->_has_operator($k))
 			{
 				// value appears not to have been set, assign the test to IS NULL
@@ -623,13 +585,13 @@ class CI_DB_postgre_driver extends CI_DB {
 
 			if ( ! is_null($v))
 			{
-				if ($escape === TRUE)
+				if (is_bool($v))
 				{
-					$v = ' '.$this->escape($v);
+					$v = ' '.($v ? 'TRUE' : 'FALSE');
 				}
-				elseif (is_bool($v))
+				elseif ($escape === TRUE)
 				{
-					$v = ($v ? ' TRUE' : ' FALSE');
+					$v = ' '.(is_int($v) ? $v : $this->escape($v));
 				}
 
 				if ( ! $this->_has_operator($k))
@@ -638,11 +600,11 @@ class CI_DB_postgre_driver extends CI_DB {
 				}
 			}
 
-			$this->qb_where[] = $prefix.$k.$v;
+			$this->{$qb_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
 			if ($this->qb_caching === TRUE)
 			{
-				$this->qb_cache_where[] = $prefix.$k.$v;
-				$this->qb_cache_exists[] = 'where';
+				$this->{$qb_cache_key}[] = array('condition' => $prefix.$k.$v, 'escape' => $escape);
+				$this->qb_cache_exists[] = substr($qb_key, 3);
 			}
 
 		}
diff --git a/system/database/drivers/postgre/postgre_forge.php b/system/database/drivers/postgre/postgre_forge.php
index c434e9510..1164d9bb3 100644
--- a/system/database/drivers/postgre/postgre_forge.php
+++ b/system/database/drivers/postgre/postgre_forge.php
@@ -39,7 +39,8 @@ class CI_DB_postgre_forge extends CI_DB_forge {
 	/**
 	 * Process Fields
 	 *
-	 * @param	mixed	the fields
+	 * @param	mixed	$fields
+	 * @param	array	$primary_keys = array()
 	 * @return	string
 	 */
 	protected function _process_fields($fields, $primary_keys = array())
@@ -190,13 +191,10 @@ class CI_DB_postgre_forge extends CI_DB_forge {
 	 * Generates a platform-specific query so that a table can be altered
 	 * Called by add_column(), drop_column(), and column_alter(),
 	 *
-	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
-	 * @param	string	the column name
-	 * @param	string	the table name
-	 * @param	string	the column definition
-	 * @param	string	the default value
-	 * @param	bool	should 'NOT NULL' be added
-	 * @param	string	the field after which we should add the new field
+	 * @param	string	$alter_type	the ALTER type (ADD, DROP, CHANGE)
+	 * @param	string	$table		the table name
+	 * @param	string	$fields		the column definition
+	 * @param	string	$after_field = ''
 	 * @return	string
 	 */
 	protected function _alter_table($alter_type, $table, $fields, $after_field = '')
diff --git a/system/database/drivers/postgre/postgre_result.php b/system/database/drivers/postgre/postgre_result.php
index eb9d647e7..458ae869c 100644
--- a/system/database/drivers/postgre/postgre_result.php
+++ b/system/database/drivers/postgre/postgre_result.php
@@ -131,6 +131,7 @@ class CI_DB_postgre_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/sqlite/sqlite_driver.php b/system/database/drivers/sqlite/sqlite_driver.php
index 19824dbbf..2fd39346f 100644
--- a/system/database/drivers/sqlite/sqlite_driver.php
+++ b/system/database/drivers/sqlite/sqlite_driver.php
@@ -45,10 +45,6 @@ class CI_DB_sqlite_driver extends CI_DB {
 	// The character used to escape with - not needed for SQLite
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' Random()'; // database specific random keyword
 
 	/**
@@ -131,6 +127,7 @@ class CI_DB_sqlite_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
diff --git a/system/database/drivers/sqlite/sqlite_result.php b/system/database/drivers/sqlite/sqlite_result.php
index eef9787a1..214841412 100644
--- a/system/database/drivers/sqlite/sqlite_result.php
+++ b/system/database/drivers/sqlite/sqlite_result.php
@@ -115,6 +115,7 @@ class CI_DB_sqlite_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	int	$n = 0
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/sqlite3/sqlite3_driver.php b/system/database/drivers/sqlite3/sqlite3_driver.php
index cc35d319f..22c72b9b8 100644
--- a/system/database/drivers/sqlite3/sqlite3_driver.php
+++ b/system/database/drivers/sqlite3/sqlite3_driver.php
@@ -46,10 +46,6 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = ' ESCAPE \'%s\' ';
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' RANDOM()';
 
 	/**
@@ -107,13 +103,12 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	/**
 	 * Execute the query
 	 *
-	 * @param	string	an SQL query
+	 * @todo	Implement use of SQLite3::querySingle(), if needed
+	 * @param	string	$sql
 	 * @return	mixed	SQLite3Result object or bool
 	 */
 	protected function _execute($sql)
 	{
-		// TODO: Implement use of SQLite3::querySingle(), if needed
-
 		return $this->is_write_type($sql)
 			? $this->conn_id->exec($sql)
 			: $this->conn_id->query($sql);
@@ -124,6 +119,7 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -288,25 +284,16 @@ class CI_DB_sqlite3_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * The error message string
+	 * Error
 	 *
-	 * @return	string
-	 */
-	protected function _error_message()
-	{
-		return $this->conn_id->lastErrorMsg();
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * The error message number
+	 * Returns an array containing code and message of the last
+	 * database error that has occured.
 	 *
-	 * @return	int
+	 * @return	array
 	 */
-	protected function _error_number()
+	public function error()
 	{
-		return $this->conn_id->lastErrorCode();
+		return array('code' => $this->conn_id->lastErrorCode(), 'message' => $this->conn_id->lastErrorMsg());
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/database/drivers/sqlite3/sqlite3_result.php b/system/database/drivers/sqlite3/sqlite3_result.php
index 117fb3ce8..35aecda36 100644
--- a/system/database/drivers/sqlite3/sqlite3_result.php
+++ b/system/database/drivers/sqlite3/sqlite3_result.php
@@ -167,6 +167,7 @@ class CI_DB_sqlite3_result extends CI_DB_result {
 	 * this internally before fetching results to make sure the
 	 * result set starts at zero
 	 *
+	 * @param	$n = 0	(ignored)
 	 * @return	array
 	 */
 	protected function _data_seek($n = 0)
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index 8bd18bd76..32f1a59d6 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -45,10 +45,6 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// The character used for escaping
 	protected $_escape_char = '"';
 
-	// clause and character used for LIKE escape sequences
-	protected $_like_escape_str = " ESCAPE '%s' ";
-	protected $_like_escape_chr = '!';
-
 	protected $_random_keyword = ' NEWID()';
 
 	// SQLSRV-specific properties
@@ -57,19 +53,21 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Non-persistent database connection
 	 *
+	 * @param	bool	$pooling = FALSE
 	 * @return	resource
 	 */
 	public function db_connect($pooling = FALSE)
 	{
-		// Check for a UTF-8 charset being passed as CI's default 'utf8'.
-		$character_set = (0 === strcasecmp('utf8', $this->char_set)) ? 'UTF-8' : $this->char_set;
+		$charset = in_array(strtolower($this->char_set), array('utf-8', 'utf8'), TRUE)
+			? 'UTF-8' : SQLSRV_ENC_CHAR;
 
 		$connection = array(
 			'UID'			=> empty($this->username) ? '' : $this->username,
 			'PWD'			=> empty($this->password) ? '' : $this->password,
 			'Database'		=> $this->database,
-			'ConnectionPooling'	=> $pooling ? 1 : 0,
-			'CharacterSet'		=> $character_set,
+			'ConnectionPooling'	=> ($pooling === TRUE) ? 1 : 0,
+			'CharacterSet'		=> $charset,
+			'Encrypt'		=> ($this->encrypt === TRUE) ? 1 : 0,
 			'ReturnDatesAsStrings'	=> 1
 		);
 
@@ -147,6 +145,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Begin Transaction
 	 *
+	 * @param	bool	$test_mode = FALSE
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
@@ -225,7 +224,7 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 */
 	public function affected_rows()
 	{
-		return sqlrv_rows_affected($this->result_id);
+		return sqlsrv_rows_affected($this->result_id);
 	}
 
 	// --------------------------------------------------------------------
@@ -362,49 +361,19 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the update data
-	 * @param	array	the where clause
-	 * @param	array	the orderby clause (ignored)
-	 * @param	array	the limit clause (ignored)
-	 * @param	array	the like clause
 	 * @return	string
 	 */
-	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	protected function _update($table, $values)
 	{
-		foreach ($values as $key => $val)
-		{
-			$valstr[] = $key.' = '.$val;
-		}
-
-		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
-
-		if ( ! empty($like))
-		{
-			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
-		}
-
-		return 'UPDATE '.$table.' SET '.implode(', ', $valstr).$where;
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
@@ -433,23 +402,16 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	array	the like clause
-	 * @param	string	the limit clause
 	 * @return	string
 	 */
-	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	protected function _delete($table)
 	{
-		$conditions = array();
-
-		empty($where) OR $conditions[] = implode(' ', $where);
-		empty($like) OR $conditions[] = implode(' ', $like);
-
-		$conditions = (count($conditions) > 0) ? ' WHERE '.implode(' AND ', $conditions) : '';
+		if ($this->qb_limit)
+		{
+			return 'WITH ci_delete AS (SELECT TOP '.$this->qb_limit.' * FROM '.$table.$this->_compile_wh('qb_where').') DELETE FROM ci_delete';
+		}
 
-		return ($limit)
-			? 'WITH ci_delete AS (SELECT TOP '.$limit.' * FROM '.$table.$conditions.') DELETE FROM ci_delete'
-			: 'DELETE FROM '.$table.$conditions;
+		return parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
@@ -460,32 +422,49 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 * 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
 	 * @return	string
 	 */
-	protected function _limit($sql, $limit, $offset)
+	protected function _limit($sql)
 	{
 		// As of SQL Server 2012 (11.0.*) OFFSET is supported
 		if (version_compare($this->version(), '11', '>='))
 		{
-			return $sql.' OFFSET '.(int) $offset.' ROWS FETCH NEXT '.(int) $limit.' ROWS ONLY';
+			return $sql.' OFFSET '.(int) $this->qb_offset.' ROWS FETCH NEXT '.$this->qb_limit.' ROWS ONLY';
 		}
 
-		$limit = $offset + $limit;
+		$limit = $this->qb_offset + $this->qb_limit;
 
 		// An ORDER BY clause is required for ROW_NUMBER() to work
-		if ($offset && ! empty($this->qb_orderby))
+		if ($this->qb_offset && ! empty($this->qb_orderby))
 		{
-			$orderby = 'ORDER BY '.implode(', ', $this->qb_orderby);
+			$orderby = $this->_compile_order_by();
 
 			// We have to strip the ORDER BY clause
-			$sql = trim(substr($sql, 0, strrpos($sql, 'ORDER BY '.$orderby)));
-
-			return 'SELECT '.(count($this->qb_select) === 0 ? '*' : implode(', ', $this->qb_select))." FROM (\n"
-				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.$orderby.') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
-				."\n) ".$this->escape_identifiers('CI_subquery')
-				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.((int) $offset + 1).' AND '.$limit;
+			$sql = trim(substr($sql, 0, strrpos($sql, $orderby)));
+
+			// Get the fields to select from our subquery, so that we can avoid CI_rownum appearing in the actual results
+			if (count($this->qb_select) === 0)
+			{
+				$select = '*'; // Inevitable
+			}
+			else
+			{
+				// Use only field names and their aliases, everything else is out of our scope.
+				$select = array();
+				$field_regexp = ($this->_quoted_identifier)
+					? '("[^\"]+")' : '(\[[^\]]+\])';
+				for ($i = 0, $c = count($this->qb_select); $i < $c; $i++)
+				{
+					$select[] = preg_match('/(?:\s|\.)'.$field_regexp.'$/i', $this->qb_select[$i], $m)
+						? $m[1] : $this->qb_select[$i];
+				}
+				$select = implode(', ', $select);
+			}
+
+			return 'SELECT '.$select." FROM (\n\n"
+				.preg_replace('/^(SELECT( DISTINCT)?)/i', '\\1 ROW_NUMBER() OVER('.trim($orderby).') AS '.$this->escape_identifiers('CI_rownum').', ', $sql)
+				."\n\n) ".$this->escape_identifiers('CI_subquery')
+				."\nWHERE ".$this->escape_identifiers('CI_rownum').' BETWEEN '.($this->qb_offset + 1).' AND '.$limit;
 		}
 
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$limit.' ', $sql);