MySQL Transaction+ PHP issue in Mysql

I have a code which was used in an application 开发者_运维技巧where I am having a problem in rollback. Even if I 's2' returns false rollback isn't happening i.e. table 'products' is getting droped. Can anyone explain why it isn't working or how should I change it. Note: tables are of Innodb engine..I use mysql 5.0+

    mysql_query('SET AUTOCOMMIT=0;');
    mysql_query('START TRANSACTION;');
    $sql = 'DROP TABLE '.$this->Product->tablePrefix.'products';
    $s1 = mysql_query($sql);
    $sql = 'RENAME TABLE '.$this->Product->tablePrefix.'temp12212 TO '.$this->Product->tablePrefix.'products'; 
    $s2 =mysql_query($sql);
    if($s1 && $s2){
        mysql_query('COMMIT;');
        $this->Session->setFlash('Commit Successful to Database');
    }else{
        mysql_query('ROLLBACK;');
        $this->Session->setFlash('Commit failed due to some errors<br> auto-rollbacked to previous state');
    }

DROP TABLE is one of the commands in MySql that cause a implicit commit.

http://dev.mysql.com/doc/refman/5.1/en/implicit-commit.html

Use this instead:

'RENAME TABLE '.$this->Product->tablePrefix.'products TO backup_table
, '.$this->Product->tablePrefix.'temp12212 TO '.$this->Product->tablePrefix.'products';

You cannot rollback a DROP TABLE or RENAME TABLE statement as they cause an implicit commit.

I sorted the problem this way instead!!! thanks all for your reply :-)  


 $sql = 'DROP TABLE IF EXISTS '.$this->Product->tablePrefix.'temp_backup';
        mysql_query($sql);
        $sql = 'RENAME TABLE '.$this->Product->tablePrefix.'products TO '.$this->Product->tablePrefix.'temp_backup, '.$this->Product->tablePrefix.'temp TO '.$this->Product->tablePrefix.'products'; 
        $status =mysql_query($sql);
        if($status){
            $sql = 'DROP TABLE '.$this->Product->tablePrefix.'temp_backup';
            mysql_query($sql);
            $this->Session->setFlash('Commit Successful to Database');
        }else{              
            $this->Session->setFlash('Commit failed due to some errors<br> auto-rollbacked to previous state');
        }