return (*sql.DB)(reflect.ValueOf(tx).Elem().FieldByName("db").UnsafePointer()), nil
	}

	if dbConnector, ok := connPool.(GetDBConnector); ok && dbConnector != nil {
		if sqldb, err := dbConnector.GetDBConn(); sqldb != nil || err != nil {
			return sqldb, err
		}
	}

	if sqldb, ok := connPool.(*sql.DB); ok && sqldb != nil {
		return sqldb, nil
	}

	return nil, ErrInvalidDB
}