(This demo mainly implements the functions of adding, modifying, and querying the SQL server database through the Android client. In the final analysis, the projects to be done are these basic functions, which only involve messy business logic management. This small demo can solve more than half of the technical problems. The implementation is divided into two aspects. On the one hand, the server side, first of all, connects to the sql server for interaction. On the other hand, the client side, through android, sends a request to interact with the server side and then interacts with the database.)