我写的C#针对数据库操作的框架类，包含四层构架，字段映射类,数据库操作类，业务类，UI类，四层分工协作，代码结构清晰，宜维护宜开发。-I wrote a C# class fr a mework for database operations, including the four-story structure, field mapping type, database operations class, business class