Hibernate Learning-08: Configuration-Core profile hibernate.cfg.xml, mapping file *.hbm.xml

Common Configuration for Hibernate:

1, the core configuration, there are two ways to configure

Configure with the properties file:

-hibernate.cfg.xml

Format: Key=value

Note: The mapping file (database table-entity Class) cannot be loaded in the properties file. Manual encoding must be used to load

XML format File configuration:

-hibernate.properties

Format:<property></property> Tags

In the core configuration:

(1), the required configuration

* 4 basic parameters to connect to a database

Hibernate.connection.driver_class connecting to a database driver

Hibernate.connection.url Connection Database URL

Hibernate.connection.username Database user Name

Hibernate.connection.password Database Password

*hibernate.dialect Operating Database dialect

(2), optional configuration

*hibernate.show_sql true to output SQL statements in the console

*hibernate.format_sql true to format the console output SQL statement

*hibernate.connection.autocommit true whether the transaction is automatically committed

*hibernate.hbm2ddl.auto create/create-drop/update/validate

* Create: Creates a new table each time it executes. (If you have previously had the table, delete the table and recreate it.) The use of general testing.

* Create-drop: Each time the execution, create a new table, the execution of the program after the end of the table, deleted. Used in general testing.

* Update: If there are no tables in the database, create a new table, and if so, use this table directly. You can update the structure of the table .

* Validate: The original table will be used. Verify that the mapping file is consistent with the fields that are configured in the table. Inconsistent error.

(3), mapped configuration

* Load the mapping file in the core configuration file:

* <mappingresource= "Cn/itcast/hibernate3/demo1/customer.hbm.xml"/> * loaded using manual encoding

2. Configuration of mapping files

ORM: Object and relational mappings.

* Configure Java objects and table mappings.

* Configure the mapping of classes to tables:

* Name: The full path of the class:

* Table: Names of tables: (can be omitted. Use the name of the class as the table name.)

<class name= "Cn.itcast.hibernate3.demo1.Order" table= "Orders" >

* Configure normal and field mappings:

<property name= "name" column= "name" type= "string"length= "/>"

Type: Three ways of writing

* Java type: java.lang.String

* Hibernate Type: string

* SQL Type: Cannot use the type attribute directly, need sub-label <column>

* <columnname= "name" sql-type= "varchar"/>

* Configure unique identities with primary key mappings:

* There is only one primary key form in a table:

<id name= "id" column= "id" >

* Build Policy:

* One table corresponds to multiple primary key forms: (Composite primary key:)---understand.

* <composite-id></composite-id>

* Association Relationship:

* The name sql:<queryname> is written in hql statement,<sql-queryname> is written in the SQL statement, after the predefined SQL, use, directly use the name

<queryname= "FindAll" >

From Customer

</query>

<sql-queryname= "Sqlfindall" >

SELECT * FROM Customer </sql-query>