private function expand($params)
    {
        unset($params['driver']);
        if (isset($params['file'])) {
            if ($params['file'] != '') {
                return $params['file'];
            }
        }

        $equated = [];
        foreach ($params as $key => $value) {
            if ($value == '') {
                continue;
            } else {
                $equated[] = "$key=$value";
            }
        }

        return implode(';', $equated);
    }