private function _constructPdoDsn(array $params, array $connectionOptions)
    {
        $dsn = 'sqlsrv:server=';

        if (isset($params['host'])) {
            $dsn .= $params['host'];
        }

        if (isset($params['port']) && ! empty($params['port'])) {
            $dsn .= ',' . $params['port'];
        }

        if (isset($params['dbname'])) {
            $connectionOptions['Database'] = $params['dbname'];
        }

        if (isset($params['MultipleActiveResultSets'])) {
            $connectionOptions['MultipleActiveResultSets'] = $params['MultipleActiveResultSets'] ? 'true' : 'false';
        }

        return $dsn . $this->getConnectionOptionsDsn($connectionOptions);
    }