protected function selectSQLDriver($connection)
    {
        switch (strtolower($connection)) {
            case 'mysql':
                $this->db = [
                    'driver'   => 'pdo_mysql',
                    'host'     => env('DB_HOST', '127.0.0.1'),
                    'port'     => env('DB_PORT', '3306'),
                    'dbname'   => env('DB_DATABASE', 'teamelf'),
                    'user'     => env('DB_USERNAME', 'teamelf'),
                    'password' => env('DB_PASSWORD', 'teamelf'),
                    'charset'  => 'UTF8'
                ];
                break;
            default:
                throw new Exception($connection . 'has not been supported yet! use [mysql] instead!');
        }
    }