system/database/drivers/mssql/mssql_driver.php - code-igniter-v3-giggi - Gitiles

 <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 5.2.4 or newer
  *
  * NOTICE OF LICENSE
  *
  * Licensed under the Open Software License version 3.0
  *
  * This source file is subject to the Open Software License (OSL 3.0) that is
  * bundled with this package in the files license.txt / license.rst.  It is
  * also available through the world wide web at this URL:
  * http://opensource.org/licenses/OSL-3.0
  * If you did not receive a copy of the license and are unable to obtain it
  * through the world wide web, please send an email to
  * licensing@ellislab.com so we can send you a copy immediately.
  *
  * @package		CodeIgniter
  * @author		EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
  * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
  * @link		http://codeigniter.com
  * @since		Version 1.0
  * @filesource
  */

 /**
  * MS SQL Database Adapter Class
  *
  * Note: _DB is an extender class that the app controller
  * creates dynamically based on whether the active record
  * class is being used or not.
  *
  * @package		CodeIgniter
  * @subpackage	Drivers
  * @category	Database
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/database/
  */
 class CI_DB_mssql_driver extends CI_DB {

 	public $dbdriver = 'mssql';

 	// 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 = '!';

 	/**
 	 * 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() methods.
 	 */
 	protected $_count_string = 'SELECT COUNT(*) AS ';
 	protected $_random_keyword = ' NEWID()';

 	public function __construct($params)
 	{
 		parent::__construct($params);

 		if ( ! empty($this->port))
 		{
 			$this->hostname .= (DIRECTORY_SEPARATOR === '\\' ? ',' : ':').$this->port;
 		}
 	}

 	/**
 	 * Non-persistent database connection
 	 *
 	 * @return	resource
 	 */
 	public function db_connect()
 	{
 		return @mssql_connect($this->hostname, $this->username, $this->password);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Persistent database connection
 	 *
 	 * @return	resource
 	 */
 	public function db_pconnect()
 	{
 		return @mssql_pconnect($this->hostname, $this->username, $this->password);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Select the database
 	 *
 	 * @param	string	database name
 	 * @return	bool
 	 */
 	public function db_select($database = '')
 	{
 		if ($database === '')
 		{
 			$database = $this->database;
 		}

 		// Note: The brackets are required in the event that the DB name
 		// contains reserved characters
 		if (@mssql_select_db('['.$database.']', $this->conn_id))
 		{
 			$this->database = $database;
 			return TRUE;
 		}

 		return FALSE;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Execute the query
 	 *
 	 * @param	string	an SQL query
 	 * @return	mixed	resource if rows are returned, bool otherwise
 	 */
 	protected function _execute($sql)
 	{
 		return @mssql_query($sql, $this->conn_id);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Begin Transaction
 	 *
 	 * @return	bool
 	 */
 	public function trans_begin($test_mode = FALSE)
 	{
 		// When transactions are nested we only begin/commit/rollback the outermost ones
 		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}

 		// 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);

 		return $this->simple_query('BEGIN TRAN');
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Commit Transaction
 	 *
 	 * @return	bool
 	 */
 	public function trans_commit()
 	{
 		// When transactions are nested we only begin/commit/rollback the outermost ones
 		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}

 		return $this->simple_query('COMMIT TRAN');
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Rollback Transaction
 	 *
 	 * @return	bool
 	 */
 	public function trans_rollback()
 	{
 		// When transactions are nested we only begin/commit/rollback the outermost ones
 		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
 		{
 			return TRUE;
 		}

 		return $this->simple_query('ROLLBACK TRAN');
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Escape String
 	 *
 	 * @param	string
 	 * @param	bool	whether or not the string will be used in a LIKE condition
 	 * @return	string
 	 */
 	public function escape_str($str, $like = FALSE)
 	{
 		if (is_array($str))
 		{
 			foreach ($str as $key => $val)
 			{
 				$str[$key] = $this->escape_str($val, $like);
 			}

 			return $str;
 		}

 		// Escape single quotes
 		$str = str_replace("'", "''", remove_invisible_characters($str));

 		// escape LIKE condition wildcards
 		if ($like === TRUE)
 		{
 			return str_replace(
 				array($this->_like_escape_chr, '%', '_'),
 				array($this->_like_escape_chr.$this->_like_escape_chr, $this->_like_escape_chr.'%', $this->_like_escape_chr.'_'),
 				$str
 			);
 		}

 		return $str;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Affected Rows
 	 *
 	 * @return	int
 	 */
 	public function affected_rows()
 	{
 		return @mssql_rows_affected($this->conn_id);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Insert ID
 	 *
 	 * Returns the last id created in the Identity column.
 	 *
 	 * @return	string
 	 */
 	public function insert_id()
 	{
 		$query = (self::_parse_major_version($this->version()) > 7)
 			? 'SELECT SCOPE_IDENTITY() AS last_id'
 			: 'SELECT @@IDENTITY AS last_id';

 		$query = $this->query($query);
 		$query = $query->row();
 		return $query->last_id;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Parse major version
 	 *
 	 * Grabs the major version number from the
 	 * database server version string passed in.
 	 *
 	 * @param	string	$version
 	 * @return	int	major version number
 	 */
 	protected function _parse_major_version($version)
 	{
 		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.
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Version number query string
 	 *
 	 * @return	string
 	 */
 	protected function _version()
 	{
 		return 'SELECT @@VERSION AS ver';
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * "Count All" query
 	 *
 	 * Generates a platform-specific query string that counts all records in
 	 * the specified database
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	public function count_all($table = '')
 	{
 		if ($table == '')
 		{
 			return 0;
 		}

 		$query = $this->query($this->_count_string.$this->protect_identifiers('numrows').' FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE));
 		if ($query->num_rows() == 0)
 		{
 			return 0;
 		}

 		$row = $query->row();
 		$this->_reset_select();
 		return (int) $row->numrows;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * List table query
 	 *
 	 * Generates a platform-specific query string so that the table names can be fetched
 	 *
 	 * @param	bool
 	 * @return	string
 	 */
 	protected function _list_tables($prefix_limit = FALSE)
 	{
 		$sql = "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";

 		// for future compatibility
 		if ($prefix_limit !== FALSE AND $this->dbprefix != '')
 		{
 			//$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
 			return FALSE; // not currently supported
 		}

 		return $sql;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * List column query
 	 *
 	 * Generates a platform-specific query string so that the column names can be fetched
 	 *
 	 * @param	string	the table name
 	 * @return	string
 	 */
 	protected function _list_columns($table = '')
 	{
 		return "SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = '".$table."'";
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Field data query
 	 *
 	 * Generates a platform-specific query so that the column data can be retrieved
 	 *
 	 * @param	string	the table name
 	 * @return	string
 	 */
 	protected function _field_data($table)
 	{
 		return 'SELECT TOP 1 * FROM '.$table;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Error
 	 *
 	 * Returns an array containing code and message of the last
 	 * database error that has occured.
 	 *
 	 * @return	array
 	 */
 	public function error()
 	{
 		$query = $this->query('SELECT @@ERROR AS code');
 		$query = $query->row();
 		return array('code' => $query->code, 'message' => mssql_get_last_message());
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Escape the SQL Identifiers
 	 *
 	 * This function escapes column and table names
 	 *
 	 * @param	string
 	 * @return	string
 	 */
 	public function _escape_identifiers($item)
 	{
 		if ($this->_escape_char == '')
 		{
 			return $item;
 		}

 		foreach ($this->_reserved_identifiers as $id)
 		{
 			if (strpos($item, '.'.$id) !== FALSE)
 			{
 				$item = str_replace('.', $this->_escape_char.'.', $item);

 				// remove duplicates if the user already included the escape
 				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item);
 			}
 		}

 		if (strpos($item, '.') !== FALSE)
 		{
 			$item = str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item);
 		}

 		// remove duplicates if the user already included the escape
 		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item.$this->_escape_char);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * 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($tables)
 	{
 		if ( ! is_array($tables))
 		{
 			$tables = array($tables);
 		}

 		return implode(', ', $tables);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Insert statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the insert keys
 	 * @param	array	the insert values
 	 * @return	string
 	 */
 	protected function _insert($table, $keys, $values)
 	{
 		return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * 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
 	 * @return	string
 	 */
 	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
 	{
 		foreach ($values as $key => $val)
 		{
 			$valstr[] = $key.' = '.$val;
 		}

 		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
 			.(($where != '' && count($where) > 0) ? ' WHERE '.implode(' ', $where) : '')
 			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '')
 			.( ! $limit ? '' : ' LIMIT '.$limit);
 	}


 	// --------------------------------------------------------------------

 	/**
 	 * Truncate 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"
 	 *
 	 * @param	string	the table name
 	 * @return	string
 	 */
 	protected function _truncate($table)
 	{
 		return 'TRUNCATE '.$table;
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Delete statement
 	 *
 	 * Generates a platform-specific delete string from the supplied data
 	 *
 	 * @param	string	the table name
 	 * @param	array	the where clause
 	 * @param	string	the limit clause
 	 * @return	string
 	 */
 	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
 	{
 		$conditions = '';
 		if (count($where) > 0 OR count($like) > 0)
 		{
 			$conditions .= "\nWHERE ".implode("\n", $this->ar_where)
 					.((count($where) > 0 && count($like) > 0) ? ' AND ' : '')
 					.implode("\n", $like);
 		}

 		return 'DELETE FROM '.$table.$conditions.( ! $limit ? '' : ' LIMIT '.$limit);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Limit string
 	 *
 	 * 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, $offset)
 	{
 		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.($limit + $offset).' ', $sql);
 	}

 	// --------------------------------------------------------------------

 	/**
 	 * Close DB Connection
 	 *
 	 * @param	resource
 	 * @return	void
 	 */
 	protected function _close($conn_id)
 	{
 		@mssql_close($conn_id);
 	}

 }

 /* End of file mssql_driver.php */
 /* Location: ./system/database/drivers/mssql/mssql_driver.php */
	<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP 5.2.4 or newer
	*
	* NOTICE OF LICENSE
	*
	* Licensed under the Open Software License version 3.0
	*
	* This source file is subject to the Open Software License (OSL 3.0) that is
	* bundled with this package in the files license.txt / license.rst. It is
	* also available through the world wide web at this URL:
	* http://opensource.org/licenses/OSL-3.0
	* If you did not receive a copy of the license and are unable to obtain it
	* through the world wide web, please send an email to
	* licensing@ellislab.com so we can send you a copy immediately.
	*
	* @package CodeIgniter
	* @author EllisLab Dev Team
	* @copyright Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
	* @license http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
	* @link http://codeigniter.com
	* @since Version 1.0
	* @filesource
	*/

	/**
	* MS SQL Database Adapter Class
	*
	* Note: _DB is an extender class that the app controller
	* creates dynamically based on whether the active record
	* class is being used or not.
	*
	* @package CodeIgniter
	* @subpackage Drivers
	* @category Database
	* @author EllisLab Dev Team
	* @link http://codeigniter.com/user_guide/database/
	*/
	class CI_DB_mssql_driver extends CI_DB {

	public $dbdriver = 'mssql';

	// 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 = '!';

	/**
	* 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() methods.
	*/
	protected $_count_string = 'SELECT COUNT(*) AS ';
	protected $_random_keyword = ' NEWID()';

	public function __construct($params)
	{
	parent::__construct($params);

	if ( ! empty($this->port))
	{
	$this->hostname .= (DIRECTORY_SEPARATOR === '\\' ? ',' : ':').$this->port;
	}
	}

	/**
	* Non-persistent database connection
	*
	* @return resource
	*/
	public function db_connect()
	{
	return @mssql_connect($this->hostname, $this->username, $this->password);
	}

	// --------------------------------------------------------------------

	/**
	* Persistent database connection
	*
	* @return resource
	*/
	public function db_pconnect()
	{
	return @mssql_pconnect($this->hostname, $this->username, $this->password);
	}

	// --------------------------------------------------------------------

	/**
	* Select the database
	*
	* @param string database name
	* @return bool
	*/
	public function db_select($database = '')
	{
	if ($database === '')
	{
	$database = $this->database;
	}

	// Note: The brackets are required in the event that the DB name
	// contains reserved characters
	if (@mssql_select_db('['.$database.']', $this->conn_id))
	{
	$this->database = $database;
	return TRUE;
	}

	return FALSE;
	}

	// --------------------------------------------------------------------

	/**
	* Execute the query
	*
	* @param string an SQL query
	* @return mixed resource if rows are returned, bool otherwise
	*/
	protected function _execute($sql)
	{
	return @mssql_query($sql, $this->conn_id);
	}

	// --------------------------------------------------------------------

	/**
	* Begin Transaction
	*
	* @return bool
	*/
	public function trans_begin($test_mode = FALSE)
	{
	// When transactions are nested we only begin/commit/rollback the outermost ones
	if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
	{
	return TRUE;
	}

	// 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);

	return $this->simple_query('BEGIN TRAN');
	}

	// --------------------------------------------------------------------

	/**
	* Commit Transaction
	*
	* @return bool
	*/
	public function trans_commit()
	{
	// When transactions are nested we only begin/commit/rollback the outermost ones
	if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
	{
	return TRUE;
	}

	return $this->simple_query('COMMIT TRAN');
	}

	// --------------------------------------------------------------------

	/**
	* Rollback Transaction
	*
	* @return bool
	*/
	public function trans_rollback()
	{
	// When transactions are nested we only begin/commit/rollback the outermost ones
	if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
	{
	return TRUE;
	}

	return $this->simple_query('ROLLBACK TRAN');
	}

	// --------------------------------------------------------------------

	/**
	* Escape String
	*
	* @param string
	* @param bool whether or not the string will be used in a LIKE condition
	* @return string
	*/
	public function escape_str($str, $like = FALSE)
	{
	if (is_array($str))
	{
	foreach ($str as $key => $val)
	{
	$str[$key] = $this->escape_str($val, $like);
	}

	return $str;
	}

	// Escape single quotes
	$str = str_replace("'", "''", remove_invisible_characters($str));

	// escape LIKE condition wildcards
	if ($like === TRUE)
	{
	return str_replace(
	array($this->_like_escape_chr, '%', '_'),
	array($this->_like_escape_chr.$this->_like_escape_chr, $this->_like_escape_chr.'%', $this->_like_escape_chr.'_'),
	$str
	);
	}

	return $str;
	}

	// --------------------------------------------------------------------

	/**
	* Affected Rows
	*
	* @return int
	*/
	public function affected_rows()
	{
	return @mssql_rows_affected($this->conn_id);
	}

	// --------------------------------------------------------------------

	/**
	* Insert ID
	*
	* Returns the last id created in the Identity column.
	*
	* @return string
	*/
	public function insert_id()
	{
	$query = (self::_parse_major_version($this->version()) > 7)
	? 'SELECT SCOPE_IDENTITY() AS last_id'
	: 'SELECT @@IDENTITY AS last_id';

	$query = $this->query($query);
	$query = $query->row();
	return $query->last_id;
	}

	// --------------------------------------------------------------------

	/**
	* Parse major version
	*
	* Grabs the major version number from the
	* database server version string passed in.
	*
	* @param string $version
	* @return int major version number
	*/
	protected function _parse_major_version($version)
	{
	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.
	}

	// --------------------------------------------------------------------

	/**
	* Version number query string
	*
	* @return string
	*/
	protected function _version()
	{
	return 'SELECT @@VERSION AS ver';
	}

	// --------------------------------------------------------------------

	/**
	* "Count All" query
	*
	* Generates a platform-specific query string that counts all records in
	* the specified database
	*
	* @param string
	* @return string
	*/
	public function count_all($table = '')
	{
	if ($table == '')
	{
	return 0;
	}

	$query = $this->query($this->_count_string.$this->protect_identifiers('numrows').' FROM '.$this->protect_identifiers($table, TRUE, NULL, FALSE));
	if ($query->num_rows() == 0)
	{
	return 0;
	}

	$row = $query->row();
	$this->_reset_select();
	return (int) $row->numrows;
	}

	// --------------------------------------------------------------------

	/**
	* List table query
	*
	* Generates a platform-specific query string so that the table names can be fetched
	*
	* @param bool
	* @return string
	*/
	protected function _list_tables($prefix_limit = FALSE)
	{
	$sql = "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";

	// for future compatibility
	if ($prefix_limit !== FALSE AND $this->dbprefix != '')
	{
	//$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
	return FALSE; // not currently supported
	}

	return $sql;
	}

	// --------------------------------------------------------------------

	/**
	* List column query
	*
	* Generates a platform-specific query string so that the column names can be fetched
	*
	* @param string the table name
	* @return string
	*/
	protected function _list_columns($table = '')
	{
	return "SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = '".$table."'";
	}

	// --------------------------------------------------------------------

	/**
	* Field data query
	*
	* Generates a platform-specific query so that the column data can be retrieved
	*
	* @param string the table name
	* @return string
	*/
	protected function _field_data($table)
	{
	return 'SELECT TOP 1 * FROM '.$table;
	}

	// --------------------------------------------------------------------

	/**
	* Error
	*
	* Returns an array containing code and message of the last
	* database error that has occured.
	*
	* @return array
	*/
	public function error()
	{
	$query = $this->query('SELECT @@ERROR AS code');
	$query = $query->row();
	return array('code' => $query->code, 'message' => mssql_get_last_message());
	}

	// --------------------------------------------------------------------

	/**
	* Escape the SQL Identifiers
	*
	* This function escapes column and table names
	*
	* @param string
	* @return string
	*/
	public function _escape_identifiers($item)
	{
	if ($this->_escape_char == '')
	{
	return $item;
	}

	foreach ($this->_reserved_identifiers as $id)
	{
	if (strpos($item, '.'.$id) !== FALSE)
	{
	$item = str_replace('.', $this->_escape_char.'.', $item);

	// remove duplicates if the user already included the escape
	return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item);
	}
	}

	if (strpos($item, '.') !== FALSE)
	{
	$item = str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item);
	}

	// remove duplicates if the user already included the escape
	return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $this->_escape_char.$item.$this->_escape_char);
	}

	// --------------------------------------------------------------------

	/**
	* 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($tables)
	{
	if ( ! is_array($tables))
	{
	$tables = array($tables);
	}

	return implode(', ', $tables);
	}

	// --------------------------------------------------------------------

	/**
	* Insert statement
	*
	* Generates a platform-specific insert string from the supplied data
	*
	* @param string the table name
	* @param array the insert keys
	* @param array the insert values
	* @return string
	*/
	protected function _insert($table, $keys, $values)
	{
	return 'INSERT INTO '.$table.' ('.implode(', ', $keys).') VALUES ('.implode(', ', $values).')';
	}

	// --------------------------------------------------------------------

	/**
	* 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
	* @return string
	*/
	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE)
	{
	foreach ($values as $key => $val)
	{
	$valstr[] = $key.' = '.$val;
	}

	return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
	.(($where != '' && count($where) > 0) ? ' WHERE '.implode(' ', $where) : '')
	.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '')
	.( ! $limit ? '' : ' LIMIT '.$limit);
	}


	// --------------------------------------------------------------------

	/**
	* Truncate 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"
	*
	* @param string the table name
	* @return string
	*/
	protected function _truncate($table)
	{
	return 'TRUNCATE '.$table;
	}

	// --------------------------------------------------------------------

	/**
	* Delete statement
	*
	* Generates a platform-specific delete string from the supplied data
	*
	* @param string the table name
	* @param array the where clause
	* @param string the limit clause
	* @return string
	*/
	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
	{
	$conditions = '';
	if (count($where) > 0 OR count($like) > 0)
	{
	$conditions .= "\nWHERE ".implode("\n", $this->ar_where)
	.((count($where) > 0 && count($like) > 0) ? ' AND ' : '')
	.implode("\n", $like);
	}

	return 'DELETE FROM '.$table.$conditions.( ! $limit ? '' : ' LIMIT '.$limit);
	}

	// --------------------------------------------------------------------

	/**
	* Limit string
	*
	* 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, $offset)
	{
	return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.($limit + $offset).' ', $sql);
	}

	// --------------------------------------------------------------------

	/**
	* Close DB Connection
	*
	* @param resource
	* @return void
	*/
	protected function _close($conn_id)
	{
	@mssql_close($conn_id);
	}

	}

	/* End of file mssql_driver.php */
	/* Location: ./system/database/drivers/mssql/mssql_driver.php */