Preliminary complex with the IDC charging system diagram

I started to draw the UML diagram from June 1. Now it's over a month and a half! Let's talk about my feelings with UML diagrams over the past one and a half months:

Phase 1: September 5-September 5

1. Example Diagram

The use case diagram mainly refers to the functional model diagram of the system, and has the first drawing experience of the charging system of the data center. Therefore, this use case diagram is the simplest and not tangled!

2. Package Diagram in step 2

It is mainly based on the classic three-tier architecture. It mainly consists of the entity layer, interface layer, business logic layer and data access layer. I have learned three layers of theory and practice before, so it is not difficult to create a classic three-layer architecture.

Interface Layer: There is no doubt that it is the form that the user can see intuitively. below is the business logic layer, which is much more difficult to do. At this time, it is a bit confusing, what should be the basis for this business logic? After analyzing the system, we found that the entire system is one-to-one correspondence between the entity layer and the database based on the four functions of adding, deleting, modifying, and querying. From the entity layer, we can find the data access layer, data access layer: it is mainly used to operate databases, that is, to add, delete, modify, and query tables.

3. Step 3 sequence diagram

When I draw a sequence chart, I think of the use of the abstract engineering mode + reflection + configuration file. Therefore, the next phase is implemented. So first add the design mode to the package diagram, and then perform the time sequence diagram!

Stage 2: September 15-September 15

After the classic three-tier architecture is complete, I want to add the design mode to it! The most basic is the abstract factory mode + reflection + configuration file.

This phase is quite tangled, mainly because it does not understand the abstract factory mode + reflection + configuration file. When learning the design model, the reflection won't be readable! You can ignore it for the last time you did not understand it, because we didn't use it, but this time it didn't work, so you must understand it! First, let's look back at the point of knowledge about the abstract factory model in the big talk design model, and then look for information online and find an example of the application of the abstract engineering model in the three layers. The last step is to open the Knife Using the login form of the data center billing system. This time, I have a further understanding of the usage of abstract factory mode + reflection + configuration files. This also proves that learning is a process. At the beginning, we didn't understand this part, but when you use it, it is much easier for you to go back and learn it. Taking this model as an example, when we were studying the design model, we were going to learn 23 models. Now we think our mind is still turbid. However, because of the system requirements, we need to know the abstract factory model. At this time, we have the purpose to learn a specific model, greatly reducing the amount of new knowledge. So it would be much easier. If we had to understand the 23 models one by one at the beginning, wouldn't we be so tired?

Next, we will re-Modify the package chart based on the first stage, and add the abstract factory mode.

The next step is to draw a sequence chart, where there has been no progress for two days. I don't know what to do? I think there is something wrong with the package diagram (layer B) I drew above. So I checked my previous figure with the tutor:

After the instructor's inspection, the problems and needs to be improved during the drawing process are as follows:

1. use case diagram: it should be drawn under the use case view, and I have stacked all the diagrams together.

2. Sequence diagram:

A. Because the sequence chart is mainly implemented based on functions, a sequence chart should correspond to a use case and should be drawn below the use case diagram.

B. The method called by the sequence chart has no parameters or return values.

C. the main function of the factory is to create objects and generate interfaces through reflection instances. Therefore, there should be no calling relationship between the factory layer and the data access layer. Instead, after the factory creates an object, return to the business logic layer, and then call the method.

3. Package diagram:

A. the division of layer B should be based on the business logic. The main function of layer B is to decouple, that is, isolate direct operations on the database, however, I divided the database based on the addition, deletion, modification, and query functions. It was obvious that I was linked to the database again!

B. D-layer naming reference specifications, methods are not fully considered, and parameters and return values are required.

C. The policy mode and Singleton mode are recommended.

All in all, in the course of learning, we should keep ourselves relaxed and happy!

Always believe that learning is a happy thing!