The full name of the ORM is Object/relation Mapping, which is the object/relational database mapping. ORM can be understood as a specification that outlines the basic characteristics of such frameworks: the completion of object-oriented programming languages to relational database mapping . When the ORM framework completes the mapping, it can take advantage of the simple usability of the object-oriented programming language and the technical advantages of the relational database. The ORM framework can therefore be used as a bridge between applications and databases.
When using an object-oriented programming language for application development, object-oriented analysis (OOA), Object-oriented design (OOD), Object-oriented programming (OOP) has been used since the beginning of the project, but when access to the persistent layer database, it must be returned to the relational database access mode. It's a very bad feeling. A tool is needed to wrap relational databases into object-oriented models, which are ORM frameworks .
With an ORM framework, applications no longer have direct access to the underlying database, but instead manipulate persisted objects in an object-oriented manner, while the ORM framework translates these object-oriented operations into the underlying SQL operations.
The only function of the ORM tool is to convert the persisted object to the operation of the database by saving, deleting, modifying and so on. From then on, programmers can manipulate persisted objects in an object-oriented manner, while the ORM Framework is responsible for translating the corresponding SQL operations.
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5--Hibernate basic Usage--1 1 object/relational database mapping (ORM)