DB::rollback PHP Method

    public static function rollback()
    {
        $args = func_get_args();
        return call_user_func_array(array(DB::getMDB(), 'rollback'), $args);
    }

 public function rollback()
 {
     $this->assertFinished();
     $this->finished = true;
     if (!$this->savepointName) {
         $this->db->rollback();
     } else {
         $this->db->savepointRollback($this->savepointName);
     }
 }