db_pdo::error PHP Метод

    public function error()
    {
        if ($this->PDOStatement) {
            $error = $this->PDOStatement->errorInfo();
            $this->error = $error[1] . ':' . $error[2];
        } else {
            $this->error = '';
        }
        if ('' != $this->queryStr) {
            $this->error .= "\n [ SQL语句 ] : " . $this->queryStr;
        }
        trace($this->error, '', 'ERR');
        return $this->error;
    }