I think OO is more about thinking as a programmer. This is a basic skill, java and. the same is true for the design model. A year ago, I saw an article on msdn called the design model of ECC. That is, Engine -- Collection -- Control. Inspired by this, OO is a basic idea when we are working on a program, but there are more things, such as maintainability and scalability. I don't know whether you have carefully studied the Ibuyspy Portal program, this is a typical program that uses ECC. Everything is rendered in the form of modules. In that program, there is a Framework, which is used to configure the Portal and security and rendering modules, this is the Engine, which is abstract and highly scalable. In addition, the Duwamish program abstracts the data layer, which is designed to adapt to a variety of databases. Are you interested in discussing this issue?