Merge CodeIgniter 3 support

1 files changed, 306 insertions, 362 deletions

diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index 328c8fe7d..a43e2539a 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -1,351 +1,280 @@
-<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
- * An open source application development framework for PHP 5.1.6 or newer
+ * An open source application development framework for PHP
  *
- * @package		CodeIgniter
- * @author		ExpressionEngine Dev Team
- * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc.
- * @license		http://codeigniter.com/user_guide/license.html
- * @link		http://codeigniter.com
- * @since		Version 1.0
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	https://codeigniter.com
+ * @since	Version 2.0.3
  * @filesource
  */
-
-// ------------------------------------------------------------------------
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * SQLSRV Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
- * creates dynamically based on whether the active record
+ * creates dynamically based on whether the query builder
  * class is being used or not.
  *
  * @package		CodeIgniter
  * @subpackage	Drivers
  * @category	Database
- * @author		ExpressionEngine Dev Team
- * @link		http://codeigniter.com/user_guide/database/
+ * @author		EllisLab Dev Team
+ * @link		https://codeigniter.com/user_guide/database/
  */
 class CI_DB_sqlsrv_driver extends CI_DB {
 
-	var $dbdriver = 'sqlsrv';
-
-	// The character used for escaping
-	var $_escape_char = '';
-
-	// clause and character used for LIKE escape sequences
-	var $_like_escape_str = " ESCAPE '%s' ";
-	var $_like_escape_chr = '!';
-
-	/**
-	 * The syntax to count rows is slightly different across different
-	 * database engines, so this string appears in each driver and is
-	 * used for the count_all() and count_all_results() functions.
-	 */
-	var $_count_string = "SELECT COUNT(*) AS ";
-	var $_random_keyword = ' ASC'; // not currently supported
-
 	/**
-	 * Non-persistent database connection
+	 * Database driver
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @var	string
 	 */
-	function db_connect($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;
-
-		$connection = array(
-			'UID'				=> empty($this->username) ? '' : $this->username,
-			'PWD'				=> empty($this->password) ? '' : $this->password,
-			'Database'			=> $this->database,
-			'ConnectionPooling' => $pooling ? 1 : 0,
-			'CharacterSet'		=> $character_set,
-			'ReturnDatesAsStrings' => 1
-		);
-		
-		// If the username and password are both empty, assume this is a 
-		// 'Windows Authentication Mode' connection.
-		if(empty($connection['UID']) && empty($connection['PWD'])) {
-			unset($connection['UID'], $connection['PWD']);
-		}
-
-		return sqlsrv_connect($this->hostname, $connection);
-	}
-
-	// --------------------------------------------------------------------
+	public $dbdriver = 'sqlsrv';
 
 	/**
-	 * Persistent database connection
+	 * Scrollable flag
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
-	 */
-	function db_pconnect()
-	{
-		$this->db_connect(TRUE);
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Reconnect
+	 * Determines what cursor type to use when executing queries.
 	 *
-	 * Keep / reestablish the db connection if no queries have been
-	 * sent for a length of time exceeding the server's idle timeout
+	 * FALSE or SQLSRV_CURSOR_FORWARD would increase performance,
+	 * but would disable num_rows() (and possibly insert_id())
 	 *
-	 * @access	public
-	 * @return	void
+	 * @var	mixed
 	 */
-	function reconnect()
-	{
-		// not implemented in MSSQL
-	}
+	public $scrollable;
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Select the database
+	 * ORDER BY random keyword
 	 *
-	 * @access	private called by the base class
-	 * @return	resource
+	 * @var	array
 	 */
-	function db_select()
-	{
-		return $this->_execute('USE ' . $this->database);
-	}
-
-	// --------------------------------------------------------------------
+	protected $_random_keyword = array('NEWID()', 'RAND(%d)');
 
 	/**
-	 * Set client character set
+	 * Quoted identifier flag
 	 *
-	 * @access	public
-	 * @param	string
-	 * @param	string
-	 * @return	resource
+	 * Whether to use SQL-92 standard quoted identifier
+	 * (double quotes) or brackets for identifier escaping.
+	 *
+	 * @var	bool
 	 */
-	function db_set_charset($charset, $collation)
-	{
-		// @todo - add support if needed
-		return TRUE;
-	}
+	protected $_quoted_identifier = TRUE;
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Execute the query
+	 * Class constructor
 	 *
-	 * @access	private called by the base class
-	 * @param	string	an SQL query
-	 * @return	resource
+	 * @param	array	$params
+	 * @return	void
 	 */
-	function _execute($sql)
+	public function __construct($params)
 	{
-		$sql = $this->_prep_query($sql);
-		return sqlsrv_query($this->conn_id, $sql, null, array(
-			'Scrollable'				=> SQLSRV_CURSOR_STATIC,
-			'SendStreamParamsAtExec'	=> true
-		));
+		parent::__construct($params);
+
+		// This is only supported as of SQLSRV 3.0
+		if ($this->scrollable === NULL)
+		{
+			$this->scrollable = defined('SQLSRV_CURSOR_CLIENT_BUFFERED')
+				? SQLSRV_CURSOR_CLIENT_BUFFERED
+				: FALSE;
+		}
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Prep the query
+	 * Database connection
 	 *
-	 * If needed, each database adapter can prep the query string
-	 *
-	 * @access	private called by execute()
-	 * @param	string	an SQL query
-	 * @return	string
+	 * @param	bool	$pooling
+	 * @return	resource
 	 */
-	function _prep_query($sql)
+	public function db_connect($pooling = FALSE)
 	{
-		return $sql;
-	}
+		$charset = in_array(strtolower($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 === TRUE) ? 1 : 0,
+			'CharacterSet'		=> $charset,
+			'Encrypt'		=> ($this->encrypt === TRUE) ? 1 : 0,
+			'ReturnDatesAsStrings'	=> 1
+		);
 
-	/**
-	 * Begin Transaction
-	 *
-	 * @access	public
-	 * @return	bool
-	 */
-	function trans_begin($test_mode = FALSE)
-	{
-		if ( ! $this->trans_enabled)
+		// If the username and password are both empty, assume this is a
+		// 'Windows Authentication Mode' connection.
+		if (empty($connection['UID']) && empty($connection['PWD']))
 		{
-			return TRUE;
+			unset($connection['UID'], $connection['PWD']);
 		}
 
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if (FALSE !== ($this->conn_id = sqlsrv_connect($this->hostname, $connection)))
 		{
-			return TRUE;
+			// Determine how identifiers are escaped
+			$query = $this->query('SELECT CASE WHEN (@@OPTIONS | 256) = @@OPTIONS THEN 1 ELSE 0 END AS qi');
+			$query = $query->row_array();
+			$this->_quoted_identifier = empty($query) ? FALSE : (bool) $query['qi'];
+			$this->_escape_char = ($this->_quoted_identifier) ? '"' : array('[', ']');
 		}
 
-		// Reset the transaction failure flag.
-		// If the $test_mode flag is set to TRUE transactions will be rolled back
-		// even if the queries produce a successful result.
-		$this->_trans_failure = ($test_mode === TRUE) ? TRUE : FALSE;
-
-		return sqlsrv_begin_transaction($this->conn_id);
+		return $this->conn_id;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Commit Transaction
+	 * Select the database
 	 *
-	 * @access	public
+	 * @param	string	$database
 	 * @return	bool
 	 */
-	function trans_commit()
+	public function db_select($database = '')
 	{
-		if ( ! $this->trans_enabled)
+		if ($database === '')
 		{
-			return TRUE;
+			$database = $this->database;
 		}
 
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
+		if ($this->_execute('USE '.$this->escape_identifiers($database)))
 		{
+			$this->database = $database;
+			$this->data_cache = array();
 			return TRUE;
 		}
 
-		return sqlsrv_commit($this->conn_id);
+		return FALSE;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Rollback Transaction
+	 * Execute the query
 	 *
-	 * @access	public
-	 * @return	bool
+	 * @param	string	$sql	an SQL query
+	 * @return	resource
 	 */
-	function trans_rollback()
+	protected function _execute($sql)
 	{
-		if ( ! $this->trans_enabled)
-		{
-			return TRUE;
-		}
-
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ($this->_trans_depth > 0)
-		{
-			return TRUE;
-		}
-
-		return sqlsrv_rollback($this->conn_id);
+		return ($this->scrollable === FALSE OR $this->is_write_type($sql))
+			? sqlsrv_query($this->conn_id, $sql)
+			: sqlsrv_query($this->conn_id, $sql, NULL, array('Scrollable' => $this->scrollable));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Escape String
+	 * Begin Transaction
 	 *
-	 * @access	public
-	 * @param	string
-	 * @param	bool	whether or not the string will be used in a LIKE condition
-	 * @return	string
+	 * @return	bool
 	 */
-	function escape_str($str, $like = FALSE)
+	protected function _trans_begin()
 	{
-		// Escape single quotes
-		return str_replace("'", "''", $str);
+		return sqlsrv_begin_transaction($this->conn_id);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Affected Rows
+	 * Commit Transaction
 	 *
-	 * @access	public
-	 * @return	integer
+	 * @return	bool
 	 */
-	function affected_rows()
+	protected function _trans_commit()
 	{
-		return @sqlrv_rows_affected($this->conn_id);
+		return sqlsrv_commit($this->conn_id);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	* Insert ID
-	*
-	* Returns the last id created in the Identity column.
-	*
-	* @access public
-	* @return integer
-	*/
-	function insert_id()
+	 * Rollback Transaction
+	 *
+	 * @return	bool
+	 */
+	protected function _trans_rollback()
 	{
-		return $this->query('select @@IDENTITY as insert_id')->row('insert_id');
+		return sqlsrv_rollback($this->conn_id);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	* Parse major version
-	*
-	* Grabs the major version number from the
-	* database server version string passed in.
-	*
-	* @access private
-	* @param string $version
-	* @return int16 major version number
-	*/
-	function _parse_major_version($version)
+	 * Affected Rows
+	 *
+	 * @return	int
+	 */
+	public function affected_rows()
 	{
-		preg_match('/([0-9]+)\.([0-9]+)\.([0-9]+)/', $version, $ver_info);
-		return $ver_info[1]; // return the major version b/c that's all we're interested in.
+		return sqlsrv_rows_affected($this->result_id);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	* Version number query string
-	*
-	* @access public
-	* @return string
-	*/
-	function _version()
+	 * Insert ID
+	 *
+	 * Returns the last id created in the Identity column.
+	 *
+	 * @return	string
+	 */
+	public function insert_id()
 	{
-		$info = sqlsrv_server_info($this->conn_id);
-		return sprintf("select '%s' as ver", $info['SQLServerVersion']);
+		return $this->query('SELECT SCOPE_IDENTITY() AS insert_id')->row()->insert_id;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * "Count All" query
-	 *
-	 * Generates a platform-specific query string that counts all records in
-	 * the specified database
+	 * Database version number
 	 *
-	 * @access	public
-	 * @param	string
 	 * @return	string
 	 */
-	function count_all($table = '')
+	public function version()
 	{
-		if ($table == '')
-			return '0';
-	
-		$query = $this->query("SELECT COUNT(*) AS numrows FROM " . $this->dbprefix . $table);
-		
-		if ($query->num_rows() == 0)
-			return '0';
-
-		$row = $query->row();
-		$this->_reset_select();
-		return $row->numrows;
+		if (isset($this->data_cache['version']))
+		{
+			return $this->data_cache['version'];
+		}
+
+		if ( ! $this->conn_id OR ($info = sqlsrv_server_info($this->conn_id)) === FALSE)
+		{
+			return FALSE;
+		}
+
+		return $this->data_cache['version'] = $info['SQLServerVersion'];
 	}
 
 	// --------------------------------------------------------------------
@@ -355,13 +284,22 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
-	 * @access	private
-	 * @param	boolean
-	 * @return	string
+	 * @param	bool
+	 * @return	string	$prefix_limit
 	 */
-	function _list_tables($prefix_limit = FALSE)
+	protected function _list_tables($prefix_limit = FALSE)
 	{
-		return "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";
+		$sql = 'SELECT '.$this->escape_identifiers('name')
+			.' FROM '.$this->escape_identifiers('sysobjects')
+			.' WHERE '.$this->escape_identifiers('type')." = 'U'";
+
+		if ($prefix_limit === TRUE && $this->dbprefix !== '')
+		{
+			$sql .= ' AND '.$this->escape_identifiers('name')." LIKE '".$this->escape_like_str($this->dbprefix)."%' "
+				.sprintf($this->_escape_like_str, $this->_escape_like_chr);
+		}
+
+		return $sql.' ORDER BY '.$this->escape_identifiers('name');
 	}
 
 	// --------------------------------------------------------------------
@@ -371,210 +309,223 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
-	 * @access	private
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
-	function _list_columns($table = '')
+	protected function _list_columns($table = '')
 	{
-		return "SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = '".$this->_escape_table($table)."'";
+		return 'SELECT COLUMN_NAME
+			FROM INFORMATION_SCHEMA.Columns
+			WHERE UPPER(TABLE_NAME) = '.$this->escape(strtoupper($table));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Field data query
-	 *
-	 * Generates a platform-specific query so that the column data can be retrieved
+	 * Returns an object with field data
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @return	object
+	 * @param	string	$table
+	 * @return	array
 	 */
-	function _field_data($table)
+	public function field_data($table)
 	{
-		return "SELECT TOP 1 * FROM " . $this->_escape_table($table);	
-	}
-
-	// --------------------------------------------------------------------
+		$sql = 'SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH, NUMERIC_PRECISION, COLUMN_DEFAULT
+			FROM INFORMATION_SCHEMA.Columns
+			WHERE UPPER(TABLE_NAME) = '.$this->escape(strtoupper($table));
 
-	/**
-	 * The error message string
-	 *
-	 * @access	private
-	 * @return	string
-	 */
-	function _error_message()
-	{
-		$error = array_shift(sqlsrv_errors());
-		return !empty($error['message']) ? $error['message'] : null;
-	}
+		if (($query = $this->query($sql)) === FALSE)
+		{
+			return FALSE;
+		}
+		$query = $query->result_object();
 
-	// --------------------------------------------------------------------
+		$retval = array();
+		for ($i = 0, $c = count($query); $i < $c; $i++)
+		{
+			$retval[$i]			= new stdClass();
+			$retval[$i]->name		= $query[$i]->COLUMN_NAME;
+			$retval[$i]->type		= $query[$i]->DATA_TYPE;
+			$retval[$i]->max_length		= ($query[$i]->CHARACTER_MAXIMUM_LENGTH > 0) ? $query[$i]->CHARACTER_MAXIMUM_LENGTH : $query[$i]->NUMERIC_PRECISION;
+			$retval[$i]->default		= $query[$i]->COLUMN_DEFAULT;
+		}
 
-	/**
-	 * The error message number
-	 *
-	 * @access	private
-	 * @return	integer
-	 */
-	function _error_number()
-	{
-		$error = array_shift(sqlsrv_errors());
-		return isset($error['SQLSTATE']) ? $error['SQLSTATE'] : null;
+		return $retval;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Escape Table Name
+	 * Error
 	 *
-	 * This function adds backticks if the table name has a period
-	 * in it. Some DBs will get cranky unless periods are escaped
+	 * Returns an array containing code and message of the last
+	 * database error that has occurred.
 	 *
-	 * @access	private
-	 * @param	string	the table name
-	 * @return	string
+	 * @return	array
 	 */
-	function _escape_table($table)
+	public function error()
 	{
-		return $table;
-	}	
-
+		$error = array('code' => '00000', 'message' => '');
+		$sqlsrv_errors = sqlsrv_errors(SQLSRV_ERR_ERRORS);
 
-	/**
-	 * Escape the SQL Identifiers
-	 *
-	 * This function escapes column and table names
-	 *
-	 * @access	private
-	 * @param	string
-	 * @return	string
-	 */
-	function _escape_identifiers($item)
-	{
-		return $item;
-	}
+		if ( ! is_array($sqlsrv_errors))
+		{
+			return $error;
+		}
 
-	// --------------------------------------------------------------------
+		$sqlsrv_error = array_shift($sqlsrv_errors);
+		if (isset($sqlsrv_error['SQLSTATE']))
+		{
+			$error['code'] = isset($sqlsrv_error['code']) ? $sqlsrv_error['SQLSTATE'].'/'.$sqlsrv_error['code'] : $sqlsrv_error['SQLSTATE'];
+		}
+		elseif (isset($sqlsrv_error['code']))
+		{
+			$error['code'] = $sqlsrv_error['code'];
+		}
 
-	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @access	public
-	 * @param	type
-	 * @return	type
-	 */
-	function _from_tables($tables)
-	{
-		if ( ! is_array($tables))
+		if (isset($sqlsrv_error['message']))
 		{
-			$tables = array($tables);
+			$error['message'] = $sqlsrv_error['message'];
 		}
 
-		return implode(', ', $tables);
+		return $error;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Insert statement
+	 * Update statement
 	 *
-	 * Generates a platform-specific insert string from the supplied data
+	 * Generates a platform-specific update string from the supplied data
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the insert keys
-	 * @param	array	the insert values
+	 * @param	string	$table
+	 * @param	array	$values
 	 * @return	string
 	 */
-	function _insert($table, $keys, $values)
-	{	
-		return "INSERT INTO ".$this->_escape_table($table)." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";
+	protected function _update($table, $values)
+	{
+		$this->qb_limit = FALSE;
+		$this->qb_orderby = array();
+		return parent::_update($table, $values);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Update statement
+	 * Truncate statement
 	 *
-	 * Generates a platform-specific update string from the supplied data
+	 * Generates a platform-specific truncate string from the supplied data
 	 *
-	 * @access	public
-	 * @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
+	 * If the database does not support the TRUNCATE statement,
+	 * then this method maps to 'DELETE FROM table'
+	 *
+	 * @param	string	$table
 	 * @return	string
 	 */
-	function _update($table, $values, $where)
+	protected function _truncate($table)
 	{
-		foreach($values as $key => $val)
-		{
-			$valstr[] = $key." = ".$val;
-		}
-	
-		return "UPDATE ".$this->_escape_table($table)." SET ".implode(', ', $valstr)." WHERE ".implode(" ", $where);
+		return 'TRUNCATE TABLE '.$table;
 	}
-	
+
 	// --------------------------------------------------------------------
 
 	/**
-	 * Truncate statement
+	 * Delete statement
 	 *
-	 * Generates a platform-specific truncate string from the supplied data
-	 * If the database does not support the truncate() command
-	 * This function maps to "DELETE FROM table"
+	 * Generates a platform-specific delete string from the supplied data
 	 *
-	 * @access	public
-	 * @param	string	the table name
+	 * @param	string	$table
 	 * @return	string
 	 */
-	function _truncate($table)
+	protected function _delete($table)
 	{
-		return "TRUNCATE TABLE ".$table;
+		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 parent::_delete($table);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Delete statement
+	 * LIMIT
 	 *
-	 * Generates a platform-specific delete string from the supplied data
+	 * Generates a platform-specific LIMIT clause
 	 *
-	 * @access	public
-	 * @param	string	the table name
-	 * @param	array	the where clause
-	 * @param	string	the limit clause
+	 * @param	string	$sql	SQL Query
 	 * @return	string
 	 */
-	function _delete($table, $where)
+	protected function _limit($sql)
 	{
-		return "DELETE FROM ".$this->_escape_table($table)." WHERE ".implode(" ", $where);
+		// As of SQL Server 2012 (11.0.*) OFFSET is supported
+		if (version_compare($this->version(), '11', '>='))
+		{
+			// SQL Server OFFSET-FETCH can be used only with the ORDER BY clause
+			empty($this->qb_orderby) && $sql .= ' ORDER BY 1';
+
+			return $sql.' OFFSET '.(int) $this->qb_offset.' ROWS FETCH NEXT '.$this->qb_limit.' ROWS ONLY';
+		}
+
+		$limit = $this->qb_offset + $this->qb_limit;
+
+		// An ORDER BY clause is required for ROW_NUMBER() to work
+		if ($this->qb_offset && ! empty($this->qb_orderby))
+		{
+			$orderby = $this->_compile_order_by();
+
+			// We have to strip the ORDER BY clause
+			$sql = trim(substr($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);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Limit string
+	 * Insert batch statement
 	 *
-	 * Generates a platform-specific LIMIT clause
+	 * Generates a platform-specific insert string from the supplied data.
 	 *
-	 * @access	public
-	 * @param	string	the sql query string
-	 * @param	integer	the number of rows to limit the query to
-	 * @param	integer	the offset value
-	 * @return	string
+	 * @param	string	$table	Table name
+	 * @param	array	$keys	INSERT keys
+	 * @param	array	$values	INSERT values
+	 * @return	string|bool
 	 */
-	function _limit($sql, $limit, $offset)
+	protected function _insert_batch($table, $keys, $values)
 	{
-		$i = $limit + $offset;
-	
-		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$i.' ', $sql);		
+		// Multiple-value inserts are only supported as of SQL Server 2008
+		if (version_compare($this->version(), '10', '>='))
+		{
+			return parent::_insert_batch($table, $keys, $values);
+		}
+
+		return ($this->db_debug) ? $this->display_error('db_unsupported_feature') : FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -582,18 +533,11 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	/**
 	 * Close DB Connection
 	 *
-	 * @access	public
-	 * @param	resource
 	 * @return	void
 	 */
-	function _close($conn_id)
+	protected function _close()
 	{
-		@sqlsrv_close($conn_id);
+		sqlsrv_close($this->conn_id);
 	}
 
 }
-
-
-
-/* End of file mssql_driver.php */
-/* Location: ./system/database/drivers/mssql/mssql_driver.php */
\ No newline at end of file