Summary of data center billing Reconstruction

The road to "Rebuilding data center fees" is coming to an end, so I dream of coding in such a month. To sum up the road of "data center billing reconstruction", we need to learn methods, pay attention to problems, and summarize knowledge!

Background of the road to data center billing reconstruction:

1. Design Mode:

The idea of the design pattern is embodied in "restructuring of Data room fees". It is an investigation of the design pattern, and the idea is applied to practice. The Charging System of the IDC uses the appearance mode, template mode, and prototype mode. You can use your own apps wherever they are.

2. Basic Cognition of layer-3 Architecture

The three-tier architecture helps us understand the main idea of layering and lay a good foundation for the project!

3. Understand the method of EA Graph

This phase is very important. It is a very important phase to draw an EA chart if you can complete the project at one time and get twice the result with half the effort! The use case diagram, class diagram, and time sequence diagram can all clarify the idea of charging data centers. In particular, in the time sequence diagram, it can determine the implementation sequence of functions to be completed, and the association between method calls and layers. The last step is to have the first experience of charging data centers. Through the first experience, the business logic of charging data centers is clearer. Avoid detours.

Summary of learning methods

Let's describe the road to rebuilding the charging system of the data center, including difficulties, gains, and sublimation. Through a series of articles, we can summarize each set of roads we have taken. What we need to learn, summarize, and think about how to reconstruct the data center billing system! As for how to learn from it, Shi Ge's blog is one of the main sources. At first, I kept reading blogs and commenting on blogs when I had no idea. The path that others walk may be the next step, and you can avoid detours.

Learning is to work with your scalp and hands-on when you don't know how to start it. Maybe we can understand it when converting from quantity to quality, understand how to do it. Summarize the difficulties and errors you have encountered. Take good OneNote notes.

Thinking and thinking are the main theme of this project. In the afternoon, I began to think about the code. I was not allowed to stop and take a half-moment off because I was afraid to interrupt my thinking and could not proceed. Thinking, independent and quiet thinking. But don't get the best of the world. It's a great job to raise the level. Why not ask?

Note:

Note: I want to talk about the flexibility and convenience of calling the database through this trial vs. Pay attention to the database usage details, A space in a small Stored Procedure statement in the database may cause the entire program to fail to run. For example, char (32) is a space char (39) is a single quotation mark, and Details determine whether the success or failure is completely apparent.Http ://

Having a general picture, we hope that we will be right from the very beginning. We cannot guarantee that we will be totally right, but we will not realize that our previous efforts are all in vain when we go back to correct the mistakes. So I mentioned EA drawing again.

Knowledge summary:

With regard to the "Data Center billing", I have more knowledge about the layered architecture. The returned value between the layer is the returned data type when sqlhelper is defined, however, the master said that when the layer and layer return tables, the coupling is greatly reduced, making the program difficult to maintain. Let yourself find a solution to this problem. Later I learned about the application of generic collections. Generic applications

There are different opinions on the appearance layer. For example, when there are many business logic such as on and off the server, the business logic of layer B is returned to the appearance layer, and the U layer directly calls the appearance layer. The concept of decoupling is completely acceptable, but for example, a simple function like querying student balances! The business logic is relatively small, and the appearance layer does not have to do so. Therefore, we should be considerate before doing so.

This project truly embodies the essence of object-oriented, such as sqlhelper abstraction, which abstracts operations on data into a simple method and can be called at will. In fact, there are still a lot of methods that are repeated this time, and they can all be abstracted. Let's make improvements later!

The most important thing in "Data Center billing" is logical thinking. Tables in the database are interrelated and database knowledge. We have learned this book "database principles, it is also a good application.

The end of each project is also a start. Accumulating experience for yourself in the future is the best result!