The concept of Hibernate--orm

1. JDBC Defects:

Hard-coding the code that interacts with the database (curd) into the JDBC program;

The object model and relational model conversions are cumbersome.

2. ORM (O/R Mapping Object Relationship mapping):

A technique for saving objects in memory to a relational database;

Responsible for the persistence of entity domain objects, encapsulating data access details;

ORM provides another pattern for persistence, using mapping Metadata (XML) to describe object-relational mapping details, enabling ORM Middleware (Hibernate) to act as a bridge between the business logic layer and the database of any Java application.

3, Business Logic Layer-----"Data access Layer (DAO, can have JDBC or hibernate to implement DAO, can be abstracted out of hibernate called the Persistence layer)------" database

4. ORM Mapping Model:

Object Model Relationship Model

Entity class/Persistence class (POJO) Table

Attribute column/Field

Uid/oid (object identifier) primary key

Object (persisted object) record

Foreign keys for association relationships between entity classes

5, the common implementation of ORM:

Hibernate is an open-source O/R mapping framework that is lightweight for JDBC and can be applied to object-oriented thinking operations database.

IBATIS (MyBatis) is also the open-source O/R mapping framework, which is a semi-automatic ORM implementation;

Toplink;castor JDO;JPA, functionally speaking, JPA is a subset of hibernate

The concept of Hibernate--orm