Layered Development Thought and Xiao Long Bao

When I was having breakfast in the morning, I suddenly had an inspiration and talked about the layered application based on the xiaolongbao I ate and my daily development experience.

First of all, let’s talk about what a three-tier architecture is. The so-called three-tier development is to divide the entire business application into presentation layer - business logic layer - data access layer - database, etc. Some are even more detailed, clearly dividing the presentation layer of the client. , business logic access, and data access and database access are divided, which is very conducive to system development, maintenance, deployment and expansion.

Software must be layered. In fact, in one sentence, it is to achieve "high cohesion and low coupling". Adopt the idea of ​​"divide and conquer" to divide the problem into individual solutions, which is easy to control, easy to extend, and easy to allocate resources.

What are the advantages of this three-layer structure?

1. By dividing the entire system into different logical blocks, the cost of application system development and maintenance is greatly reduced.

The three-tier structure separates the presentation part and business logic part according to the client layer and application server. Communication between the client and application server, application server and database server, and data exchange between heterogeneous platforms can all be done through middleware or related programs to implement. When the business logic of the database or application server changes, the client does not need to change, and vice versa, thus greatly improving the reusability of system modules, shortening the development cycle, and reducing maintenance costs.

Interesting understanding:

Suppose the restaurant makes Xiao Long Bao like this:

One layer of steamed dumplings,

A layer of meat buns,

A layer of plain bag.

First of all, in this way, we can divide the bun makers into different groups to be responsible for making different buns. When each type of bun is made, they can easily know which cage to put it in without having to check where to put it one by one. We can also easily put the cage on the fire without affecting other Cage heating. When we want to eat meat buns or steamed dumplings, we can easily find what we need, which saves time and energy. Taking away or adding more meat buns or steamed dumplings will not affect the heating of the vegetarian buns.

What do you think would happen if we put all these in a big cage? Will it be very messy and time-consuming to maintain? Not only is it troublesome to find, but every time you open the pot, it will have an impact on other things.​

2. Centralize data access and logical operations into components, enhancing the reusability of the system.

For example, data access is centralized into components of the data access layer, thereby reducing duplicate code in the application. Each form that needs to access databases and tables uses the same components.

For example: some common logical operations are encapsulated in the components of the logic layer. Each operation using this method can share access to the component.

​Interesting understanding:

To simply understand, the cage itself is an example of reuse. If we use a disposable cage (understood like disposable chopsticks), how much manpower will be wasted to do it (repetitive writing is troublesome), and there will be a huge waste of resources ( Code redundancy), and finally garbage disposal (post-maintenance). Moreover, if the cage and the stove pot are made according to a specification and standard (interface), such a cage can not only be used here, but can also be used in other places. (Although this understanding is not accurate, it is easy to understand it this way)

3. The scalability of the system is greatly enhanced.

Modularization makes the system easy to expand in both vertical and horizontal directions: on the one hand, the system can be upgraded to a larger and more powerful platform, and at the same time, the scale can be appropriately increased to enhance the network application of the system. Distributed data processing becomes possible by getting rid of the restriction of system isomorphism. When expanding or modifying functions, the stability of the original structure will basically not be destroyed.

Interesting understanding:

With the needs of customers, we now need to add new varieties, such as steamed buns and steamed sweet potatoes, so we can just add a layer of cages, which will not have any impact on other cages.​

The role of the three-tier structure in creating an enterprise's competitive advantage is mainly reflected in the modular design that allows users to achieve system expansion based on the existing structure, thereby improving the speed and business level of enterprise informatization; at the same time, the middleware in the three-tier structure The emergence of the system allows users to directly choose suitable products from the market to build systems, greatly reducing the development cycle and development costs.​

However, the hierarchical structure also has disadvantages, and more is not always better. It will be more troublesome to manage many layers, and the operating efficiency may be low. Therefore, a system with a good hierarchical structure must have the right number of layers.

Related documents: Three-tier architecture and pig farming

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