protected function createPdo(array $config)
    {
        $dsn        = $this->getHostDsn($config);
        $userName   = (isset($config['username']) ? $config['username'] : null);
        $password   = (isset($config['password']) ? $config['password'] : null);
        $options    = $this->getPdoOptions($config);

        return new PDO($dsn, $userName, $password, $options);
    }