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This article mainly explains "how to understand Hibernate persistence layer", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let Xiaobian take you to learn "How to understand Hibernate persistence layer"!

Layered architecture of applications

With the development of computer application software, application program gradually develops from single-layer architecture to multi-layer architecture. Among them, three-tier structure is a typical application software structure.

Presentation layer: provides interfaces for interaction with users, such as GUI (graphical user interface), web pages, etc.;

◆ Business logic layer: responsible for all kinds of business logic, directly access the database, provide business data save, update, delete and query operations;

Database layer: responsible for storing persistent business data for managing applications.

The characteristics of the three-layer structure are that all lower layers provide interfaces for calls to the upper layers, and the specific implementation details are transparent to the upper layers. There is a top-down dependency between layers, i.e., the upper layer accesses the API of the lower layer, but the lower layer does not depend on the upper layer.

Hibernate persistence layer

1. What is persistence?

A separate Hibernate persistence layer encapsulates data access details and provides object-oriented APIs for the business logic layer.

Persistence: saving data (such as objects in memory) to a storable storage device (such as disk). The main application of persistence is to store data in memory in relational databases, but it can also be stored in disk files, XML data files, and so on.

2. What is Hibernate Persistence Layer?

Hibernate Persistence Layer: A logical layer of a particular system focused on implementing data persistence application domains, associating data consumers with data entities.

3. Why persist? What is the effect of adding Hibernate persistence layers?

Database reading and writing is a very time-consuming and resource-consuming operation, when a large number of users directly access the database at the same time, the efficiency will be very low, if the data persistence does not need to read data from the database every time, directly in the memory to operate on the data, so as to save database resources, and speed up the system's reflection speed.

Adding Hibernate persistence improves development efficiency, makes software architecture clearer, and makes it easier to write code and maintain systems. Especially in large applications, it will be more beneficial. At the same time, persistence layer as a separate layer, people can independently develop a software package for this layer, so that it implements the persistence of various application data and provides services for the upper layer. Therefore, developers who do application development in various enterprises do not have to do the low-level implementation of data persistence, but can directly call the API provided by the persistence layer.

4. Currently in the persistence layer domain, there are several implementation patterns:

◆ Coupling of business logic and data access

Active Domain Object Model

◆ORM mode

◆JDO mode

◆CMP mode

At this point, I believe that everyone has a deeper understanding of "how to understand Hibernate persistence layer", so let's actually operate it! Here is the website, more related content can enter the relevant channels for inquiry, pay attention to us, continue to learn!

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