/lenasys/trunk

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP 5.1.6 or newer

 *

 * @package		CodeIgniter

 * @author		ExpressionEngine Dev Team

 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.

 * @license		http://codeigniter.com/user_guide/license.html

 * @link		http://codeigniter.com

 * @since		Version 1.0

 * @filesource

 */

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

/**

 * SQLSRV 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		ExpressionEngine Dev Team

 * @link		http://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

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	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);

	}

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

	/**

	 * Persistent database connection

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	function db_pconnect()

	{

		$this->db_connect(TRUE);

	}

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

	/**

	 * Reconnect

	 *

	 * Keep / reestablish the db connection if no queries have been

	 * sent for a length of time exceeding the server's idle timeout

	 *

	 * @access	public

	 * @return	void

	 */

	function reconnect()

	{

		// not implemented in MSSQL

	}

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

	/**

	 * Select the database

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	function db_select()

	{

		return $this->_execute('USE ' . $this->database);

	}

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

	/**

	 * Set client character set

	 *

	 * @access	public

	 * @param	string

	 * @param	string

	 * @return	resource

	 */

	function db_set_charset($charset, $collation)

	{

		// @todo - add support if needed

		return TRUE;

	}

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

	/**

	 * Execute the query

	 *

	 * @access	private called by the base class

	 * @param	string	an SQL query

	 * @return	resource

	 */

	function _execute($sql)

	{

		$sql = $this->_prep_query($sql);

		return sqlsrv_query($this->conn_id, $sql, null, array(

			'Scrollable'				=> SQLSRV_CURSOR_STATIC,

			'SendStreamParamsAtExec'	=> true

		));

	}

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

	/**

	 * Prep the query

	 *

	 * If needed, each database adapter can prep the query string

	 *

	 * @access	private called by execute()

	 * @param	string	an SQL query

	 * @return	string

	 */

	function _prep_query($sql)

	{

		return $sql;

	}

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

	/**

	 * Begin Transaction

	 *

	 * @access	public

	 * @return	bool

	 */

	function trans_begin($test_mode = FALSE)

	{

		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;

		}

		// 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);

	}

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

	/**

	 * Commit Transaction

	 *

	 * @access	public

	 * @return	bool

	 */

	function trans_commit()

	{

		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_commit($this->conn_id);

	}

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

	/**

	 * Rollback Transaction

	 *

	 * @access	public

	 * @return	bool

	 */

	function trans_rollback()

	{

		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);

	}

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

	/**

	 * Escape String

	 *

	 * @access	public

	 * @param	string

	 * @param	bool	whether or not the string will be used in a LIKE condition

	 * @return	string

	 */

	function escape_str($str, $like = FALSE)

	{

		// Escape single quotes

		return str_replace("'", "''", $str);

	}

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

	/**

	 * Affected Rows

	 *

	 * @access	public

	 * @return	integer

	 */

	function affected_rows()

	{

		return @sqlrv_rows_affected($this->conn_id);

	}

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

	/**

	* Insert ID

	*

	* Returns the last id created in the Identity column.

	*

	* @access public

	* @return integer

	*/

	function insert_id()

	{

		return $this->query('select @@IDENTITY as insert_id')->row('insert_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)

	{

		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

	*

	* @access public

	* @return string

	*/

	function _version()

	{

		$info = sqlsrv_server_info($this->conn_id);

		return sprintf("select '%s' as ver", $info['SQLServerVersion']);

	}

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

	/**

	 * "Count All" query

	 *

	 * Generates a platform-specific query string that counts all records in

	 * the specified database

	 *

	 * @access	public

	 * @param	string

	 * @return	string

	 */

	function count_all($table = '')

	{

		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;

	}

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

	/**

	 * List table query

	 *

	 * Generates a platform-specific query string so that the table names can be fetched

	 *

	 * @access	private

	 * @param	boolean

	 * @return	string

	 */

	function _list_tables($prefix_limit = FALSE)

	{

		return "SELECT name FROM sysobjects WHERE type = 'U' ORDER BY name";

	}

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

	/**

	 * List column query

	 *

	 * Generates a platform-specific query string so that the column names can be fetched

	 *

	 * @access	private

	 * @param	string	the table name

	 * @return	string

	 */

	function _list_columns($table = '')

	{

		return "SELECT * FROM INFORMATION_SCHEMA.Columns WHERE TABLE_NAME = '".$this->_escape_table($table)."'";

	}

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

	/**

	 * Field data query

	 *

	 * Generates a platform-specific query so that the column data can be retrieved

	 *

	 * @access	public

	 * @param	string	the table name

	 * @return	object

	 */

	function _field_data($table)

	{

		return "SELECT TOP 1 * FROM " . $this->_escape_table($table);	

	}

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

	/**

	 * The error message string

	 *

	 * @access	private

	 * @return	string

	 */

	function _error_message()

	{

		$error = array_shift(sqlsrv_errors());

		return !empty($error['message']) ? $error['message'] : null;

	}

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

	/**

	 * The error message number

	 *

	 * @access	private

	 * @return	integer

	 */

	function _error_number()

	{

		$error = array_shift(sqlsrv_errors());

		return isset($error['SQLSTATE']) ? $error['SQLSTATE'] : null;

	}

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

	/**

	 * Escape Table Name

	 *

	 * This function adds backticks if the table name has a period

	 * in it. Some DBs will get cranky unless periods are escaped

	 *

	 * @access	private

	 * @param	string	the table name

	 * @return	string

	 */

	function _escape_table($table)

	{

		return $table;

	}	

	/**

	 * Escape the SQL Identifiers

	 *

	 * This function escapes column and table names

	 *

	 * @access	private

	 * @param	string

	 * @return	string

	 */

	function _escape_identifiers($item)

	{

		return $item;

	}

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

	/**

	 * 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))

		{

			$tables = array($tables);

		}

		return implode(', ', $tables);

	}

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

	/**

	 * Insert statement

	 *

	 * Generates a platform-specific insert string from the supplied data

	 *

	 * @access	public

	 * @param	string	the table name

	 * @param	array	the insert keys

	 * @param	array	the insert values

	 * @return	string

	 */

	function _insert($table, $keys, $values)

	{	

		return "INSERT INTO ".$this->_escape_table($table)." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";

	}

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

	/**

	 * Update statement

	 *

	 * Generates a platform-specific update 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

	 * @return	string

	 */

	function _update($table, $values, $where)

	{

		foreach($values as $key => $val)

		{

			$valstr[] = $key." = ".$val;

		}

		return "UPDATE ".$this->_escape_table($table)." SET ".implode(', ', $valstr)." WHERE ".implode(" ", $where);

	}

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

	/**

	 * 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"

	 *

	 * @access	public

	 * @param	string	the table name

	 * @return	string

	 */

	function _truncate($table)

	{

		return "TRUNCATE ".$table;

	}

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

	/**

	 * Delete statement

	 *

	 * Generates a platform-specific delete string from the supplied data

	 *

	 * @access	public

	 * @param	string	the table name

	 * @param	array	the where clause

	 * @param	string	the limit clause

	 * @return	string

	 */

	function _delete($table, $where)

	{

		return "DELETE FROM ".$this->_escape_table($table)." WHERE ".implode(" ", $where);

	}

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

	/**

	 * Limit string

	 *

	 * Generates a platform-specific LIMIT clause

	 *

	 * @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

	 */

	function _limit($sql, $limit, $offset)

	{

		$i = $limit + $offset;

		return preg_replace('/(^\SELECT (DISTINCT)?)/i','\\1 TOP '.$i.' ', $sql);		

	}

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

	/**

	 * Close DB Connection

	 *

	 * @access	public

	 * @param	resource

	 * @return	void

	 */

	function _close($conn_id)

	{

		@sqlsrv_close($conn_id);

	}

}

/* End of file mssql_driver.php */

/* Location: ./system/database/drivers/mssql/mssql_driver.php */