QT 采用的是sqlite数据库，可以实现添加，编辑，删除，按各种条件删选的功能-QT USES a sqlite database, can be achieved to add, edit, delete, delete selected function according to various conditions

本系统实现了图书的增删改查功能，还有登录界面(This system implements the functions of adding and modifying books, as well as login interface)