1. Data Layer
Data layer mainly basic operation of the database, and ensure that the connection and the data connection to release resources, to avoid deadlock database; as access to a database of different frameworks have different access methods, the ORM, like direct data,
How efficiently when accessing data, simple to obtain the expected results, the content is the data access layer of concern
2. Interface Definition
Public method describes a class group / public property. It does not implement any methods or properties, just tell inherits its class, the user simply concerned with how to define the interface of neglect,
3. The entity class
4. Yewuluojiceng
The application layer