Hibernate configuration files and Object relational mapping files learn about

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One, learning case: About hibernate configuration file and Object relational mapping file understanding.

Second, case analysis:

A) Hibernate configuration file (hibernate.cfg.xml)

1. Hibernate.dialect: SQL dialect used by database

2. Hiebrnate.connection.driver_class: Database driver

3. Hibernate.connection.url: The URL of the connection database

4, Hibernate.connection.username: The user name of the connection database

5, Hibernate.connection.password: Connect the database Password

6, Hibernate.show_sql:true indicates that when the program is run, the SQL statement is output in the console , the default false

7. Hbm2ddl.auto: Create indicates that the database table will be created automatically when Hibernate starts, update Indicates that The database table structure is updated when Hibernate starts (you can test the object to add fields, modify types, and so on).

B) Object Relational mapping file (Object.hbm.xml)

1, hibernate-mapping can be configured on the package name, if you do not configure The name in the class to fill in the name of the package with the name.

2, the ID tag must be configured Fuzhou generator. Hibernate provides a lot of information that you can view in the documentation. It is recommended to use native.

3, the property on the general configuration name , the name must be the same as the field in the POJO object. Type is optional and must be filled in individual special cases, such as date, character, text, etc.

4, the above is just the general understanding of the object-relational mapping file, for a pair of more, many to one, many-to-many, one-way, bidirectional and other related relations later, this is the difficulty of hibernate.

Third, Experience:

A) The difficulty of learning about hibernate is the relationship mapping, as I am now confused by the usual. Relational mapping has been done to a great extent to our coding and functional implementation. So we're not going to do more research.

b) Hibernate in the project as long as the relational mapping is basically OK , it is mainly more database-related, and the Web program has nothing to do . It's important to remember that even if you write application, you can use hibernate.

Iv. Reference items: None.

Five, a day of joy:

The foreman said to the new worker:" you are slow to do things, slow to walk, slow to move your brains, what do you do fast?" "
The new worker said," well , I'm tired fast." "

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Hibernate configuration files and Object relational mapping files learn about