Three-layer structural programming ideology (1)

xiaoxiao2021-03-05  51

During the programming process, good development tools are important, but the development of the idea also has a pivotal role. Current popular development tools such as VB, Delphi, C Builder, etc., using these RAD development tools to develop fast and efficient software products. Because there is a large number of VCL controls available, programmers only need to drag them to the interface and write a small amount of code.

In fact, we carefully analyze it, it is not difficult to find OOP, OOD we have been advocating, in fact, in fact, it is not fully entered in the design and development of procedures, we may have been using development tools that have been provided for our package. Function. There is no idea in the entire development process of the system. With RAD development tools are convenient to develop applications, but if you develop a similar system, you have to re-develop. Cannot improve the efficiency of software development.

This article is intended to illustrate the introduction of three-layer structural idea during system development. This article will use the SQL Server database as a background database and use Delphi and C # to implement three-layer structural function classes. Since I have limited level, there is insufficient or wrong, everyone gives you to the finger, and I hope to play the role of tiles.

Three-layer structure: It mainly includes the following three levels.

Data layer: This layer is mainly encapsulated access operation classes and data entity classes. This layer is mainly related to the database table and view, which can be automatically generated by a special auxiliary tool (later will be mentioned). The realization of this layer accounts for about 20% of total development.

Application logic layer: This layer is mainly to encapsulate functional classes based on objects in the data layer according to the actual functional logic of the system. This layer is more flexible, and it is necessary to customize according to different requirements. This layer mainly rely on manual coding, and there is no shortcut to map. Should

The realization of the layer accounts for 45% of the total development.

Indicates the layer: the system interface, data exchange with the user. This layer is mainly to call the class of the application logic layer to express and implement. The realization of this layer accounts for about 35% of the total development.

Of course, in the actual development process, it can be subdivided in each layer, but its main division mode is not outside the 3 floors.

In the subsequent document, the various levels will be described and the application is performed to consolidate understanding.

(Endlessly)

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