private function _constructPdoDsn(array $params)
    {
        $dsn = 'pgsql:';

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

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

        if (isset($params['dbname'])) {
            $dsn .= 'dbname=' . $params['dbname'] . ';';
        } elseif (isset($params['default_dbname'])) {
            $dsn .= 'dbname=' . $params['default_dbname'] . ';';
        } else {
            // Used for temporary connections to allow operations like dropping the database currently connected to.
            // Connecting without an explicit database does not work, therefore "postgres" database is used
            // as it is mostly present in every server setup.
            $dsn .= 'dbname=postgres;';
        }

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

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

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

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

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

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

        return $dsn;
    }