hibernate>多对多关联映射 小强斋

多对多关联映射  （many-to-many）

多对多关联映射，需要一个中间表,Hibernate会自动生成中间表

一、多对多单向

Role.hbm.xml

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.Role" table="t_role">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
	</class>
</hibernate-mapping>

User.hbm.xml

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.User" table="t_user">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
		<set name="roles" table="t_user_role">
			<key column="userid"/>
			<many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/>
		</set>
	</class>
</hibernate-mapping>

二、多对多双向

Role.jbm.xml

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.Role" table="t_role">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
		<set name="users" table="t_user_role" order-by="userid">
			<key column="roleid"/>
			<many-to-many class="com.bjsxt.hibernate.User" column="userid"/>
		</set>
	</class>
</hibernate-mapping>

User.hbm.xml

<hibernate-mapping>
	<class name="com.bjsxt.hibernate.User" table="t_user">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
		<set name="roles" table="t_user_role">
			<key column="userid"/>
			<many-to-many class="com.bjsxt.hibernate.Role" column="roleid"/>
		</set>
	</class>
</hibernate-mapping>