<?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

 */



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



/**

 * MySQL 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_mysql_driver extends CI_DB {



	var $dbdriver = 'mysql';



	// The character used for escaping

	var	$_escape_char = '`';



	// clause and character used for LIKE escape sequences - not used in MySQL

	var $_like_escape_str = '';

	var $_like_escape_chr = '';



	/**

	 * Whether to use the MySQL "delete hack" which allows the number

	 * of affected rows to be shown. Uses a preg_replace when enabled,

	 * adding a bit more processing to all queries.

	 */

	var $delete_hack = TRUE;



	/**

	 * 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 = ' RAND()'; // database specific random keyword



	// whether SET NAMES must be used to set the character set

	var $use_set_names;

	

	/**

	 * Non-persistent database connection

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	function db_connect()

	{

		if ($this->port != '')

		{

			$this->hostname .= ':'.$this->port;

		}



		return @mysql_connect($this->hostname, $this->username, $this->password, TRUE);

	}



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



	/**

	 * Persistent database connection

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	function db_pconnect()

	{

		if ($this->port != '')

		{

			$this->hostname .= ':'.$this->port;

		}



		return @mysql_pconnect($this->hostname, $this->username, $this->password);

	}



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



	/**

	 * 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()

	{

		if (mysql_ping($this->conn_id) === FALSE)

		{

			$this->conn_id = FALSE;

		}

	}



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



	/**

	 * Select the database

	 *

	 * @access	private called by the base class

	 * @return	resource

	 */

	function db_select()

	{

		return @mysql_select_db($this->database, $this->conn_id);

	}



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



	/**

	 * Set client character set

	 *

	 * @access	public

	 * @param	string

	 * @param	string

	 * @return	resource

	 */

	function db_set_charset($charset, $collation)

	{

		if ( ! isset($this->use_set_names))

		{

			// mysql_set_charset() requires PHP >= 5.2.3 and MySQL >= 5.0.7, use SET NAMES as fallback

			$this->use_set_names = (version_compare(PHP_VERSION, '5.2.3', '>=') && version_compare(mysql_get_server_info(), '5.0.7', '>=')) ? FALSE : TRUE;

		}



		if ($this->use_set_names === TRUE)

		{

			return @mysql_query("SET NAMES '".$this->escape_str($charset)."' COLLATE '".$this->escape_str($collation)."'", $this->conn_id);

		}

		else

		{

			return @mysql_set_charset($charset, $this->conn_id);

		}

	}



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



	/**

	 * Version number query string

	 *

	 * @access	public

	 * @return	string

	 */

	function _version()

	{

		return "SELECT version() AS ver";

	}



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



	/**

	 * 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 @mysql_query($sql, $this->conn_id);

	}



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



	/**

	 * 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)

	{

		// "DELETE FROM TABLE" returns 0 affected rows This hack modifies

		// the query so that it returns the number of affected rows

		if ($this->delete_hack === TRUE)

		{

			if (preg_match('/^\s*DELETE\s+FROM\s+(\S+)\s*$/i', $sql))

			{

				$sql = preg_replace("/^\s*DELETE\s+FROM\s+(\S+)\s*$/", "DELETE FROM \\1 WHERE 1=1", $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;



		$this->simple_query('SET AUTOCOMMIT=0');

		$this->simple_query('START TRANSACTION'); // can also be BEGIN or BEGIN WORK

		return TRUE;

	}



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



	/**

	 * 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;

		}



		$this->simple_query('COMMIT');

		$this->simple_query('SET AUTOCOMMIT=1');

		return TRUE;

	}



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



	/**

	 * 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;

		}



		$this->simple_query('ROLLBACK');

		$this->simple_query('SET AUTOCOMMIT=1');

		return TRUE;

	}



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



	/**

	 * 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)

	{

		if (is_array($str))

		{

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

	   		{

				$str[$key] = $this->escape_str($val, $like);

	   		}



	   		return $str;

	   	}



		if (function_exists('mysql_real_escape_string') AND is_resource($this->conn_id))

		{

			$str = mysql_real_escape_string($str, $this->conn_id);

		}

		elseif (function_exists('mysql_escape_string'))

		{

			$str = mysql_escape_string($str);

		}

		else

		{

			$str = addslashes($str);

		}



		// escape LIKE condition wildcards

		if ($like === TRUE)

		{

			$str = str_replace(array('%', '_'), array('\\%', '\\_'), $str);

		}



		return $str;

	}



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



	/**

	 * Affected Rows

	 *

	 * @access	public

	 * @return	integer

	 */

	function affected_rows()

	{

		return @mysql_affected_rows($this->conn_id);

	}



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



	/**

	 * Insert ID

	 *

	 * @access	public

	 * @return	integer

	 */

	function insert_id()

	{

		return @mysql_insert_id($this->conn_id);

	}



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



	/**

	 * "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 = $this->query($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

	 *

	 * @access	private

	 * @param	boolean

	 * @return	string

	 */

	function _list_tables($prefix_limit = FALSE)

	{

		$sql = "SHOW TABLES FROM ".$this->_escape_char.$this->database.$this->_escape_char;



		if ($prefix_limit !== FALSE AND $this->dbprefix != '')

		{

			$sql .= " LIKE '".$this->escape_like_str($this->dbprefix)."%'";

		}



		return $sql;

	}



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



	/**

	 * Show column query

	 *

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

	 *

	 * @access	public

	 * @param	string	the table name

	 * @return	string

	 */

	function _list_columns($table = '')

	{

		return "SHOW COLUMNS FROM ".$this->_protect_identifiers($table, TRUE, NULL, FALSE);

	}



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



	/**

	 * 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 "DESCRIBE ".$table;

	}



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



	/**

	 * The error message string

	 *

	 * @access	private

	 * @return	string

	 */

	function _error_message()

	{

		return mysql_error($this->conn_id);

	}



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



	/**

	 * The error message number

	 *

	 * @access	private

	 * @return	integer

	 */

	function _error_number()

	{

		return mysql_errno($this->conn_id);

	}



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



	/**

	 * Escape the SQL Identifiers

	 *

	 * This function escapes column and table names

	 *

	 * @access	private

	 * @param	string

	 * @return	string

	 */

	function _escape_identifiers($item)

	{

		if ($this->_escape_char == '')

		{

			return $item;

		}



		foreach ($this->_reserved_identifiers as $id)

		{

			if (strpos($item, '.'.$id) !== FALSE)

			{

				$str = $this->_escape_char. str_replace('.', $this->_escape_char.'.', $item);



				// remove duplicates if the user already included the escape

				return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);

			}

		}



		if (strpos($item, '.') !== FALSE)

		{

			$str = $this->_escape_char.str_replace('.', $this->_escape_char.'.'.$this->_escape_char, $item).$this->_escape_char;

		}

		else

		{

			$str = $this->_escape_char.$item.$this->_escape_char;

		}



		// remove duplicates if the user already included the escape

		return preg_replace('/['.$this->_escape_char.']+/', $this->_escape_char, $str);

	}



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



	/**

	 * 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 ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";

	}



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





	/**

	 * Replace statement

	 *

	 * Generates a platform-specific replace 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 _replace($table, $keys, $values)

	{

		return "REPLACE INTO ".$table." (".implode(', ', $keys).") VALUES (".implode(', ', $values).")";

	}



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



	/**

	 * Insert_batch 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_batch($table, $keys, $values)

	{

		return "INSERT INTO ".$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, $orderby = array(), $limit = FALSE)

	{

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

		{

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

		}



		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;



		$orderby = (count($orderby) >= 1)?' ORDER BY '.implode(", ", $orderby):'';



		$sql = "UPDATE ".$table." SET ".implode(', ', $valstr);



		$sql .= ($where != '' AND count($where) >=1) ? " WHERE ".implode(" ", $where) : '';



		$sql .= $orderby.$limit;



		return $sql;

	}



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





	/**

	 * Update_Batch statement

	 *

	 * Generates a platform-specific batch update string from the supplied data

	 *

	 * @access	public

	 * @param	string	the table name

	 * @param	array	the update data

	 * @param	array	the where clause

	 * @return	string

	 */

	function _update_batch($table, $values, $index, $where = NULL)

	{

		$ids = array();

		$where = ($where != '' AND count($where) >=1) ? implode(" ", $where).' AND ' : '';



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

		{

			$ids[] = $val[$index];



			foreach (array_keys($val) as $field)

			{

				if ($field != $index)

				{

					$final[$field][] =  'WHEN '.$index.' = '.$val[$index].' THEN '.$val[$field];

				}

			}

		}



		$sql = "UPDATE ".$table." SET ";

		$cases = '';



		foreach ($final as $k => $v)

		{

			$cases .= $k.' = CASE '."\n";

			foreach ($v as $row)

			{

				$cases .= $row."\n";

			}



			$cases .= 'ELSE '.$k.' END, ';

		}



		$sql .= substr($cases, 0, -2);



		$sql .= ' WHERE '.$where.$index.' IN ('.implode(',', $ids).')';



		return $sql;

	}



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





	/**

	 * 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 = array(), $like = array(), $limit = FALSE)

	{

		$conditions = '';



		if (count($where) > 0 OR count($like) > 0)

		{

			$conditions = "\nWHERE ";

			$conditions .= implode("\n", $this->ar_where);



			if (count($where) > 0 && count($like) > 0)

			{

				$conditions .= " AND ";

			}

			$conditions .= implode("\n", $like);

		}



		$limit = ( ! $limit) ? '' : ' LIMIT '.$limit;



		return "DELETE FROM ".$table.$conditions.$limit;

	}



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



	/**

	 * 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)

	{

		if ($offset == 0)

		{

			$offset = '';

		}

		else

		{

			$offset .= ", ";

		}



		return $sql."LIMIT ".$offset.$limit;

	}



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



	/**

	 * Close DB Connection

	 *

	 * @access	public

	 * @param	resource

	 * @return	void

	 */

	function _close($conn_id)

	{

		@mysql_close($conn_id);

	}



}





/* End of file mysql_driver.php */

/* Location: ./system/database/drivers/mysql/mysql_driver.php */