public function session_destroy($session_id)
    {

        if (empty($session_id)) return false;

        // Build query
        $escaped_id = (string)addslashes(stripslashes($session_id));
        $sql        = (string)"DELETE FROM `{$this->_db_name}`.`user_session` WHERE `session_id` = '$escaped_id'";

        return $this->db->query((string)$sql);
    }