所有的数据管理都在类模块中进行,在窗体中不直接对结果集和字段操作 , 操作对象是类 属性和类方法.真正实现了数据管理逻辑和用户接口逻辑的分离-all the data management in the category module, the window of which do not directly result sets and field operations, Operation Object class attribute is referring. truly reali