hibernate映射关系

一对一关联

一对一单向外键关联

annotation：@OneToOne @JoinColumn

xml:<mangy-to-one unique="true">

一对一双向关联

annotation: @OneToOne(mappedBy)

xml :<many-to-one unique="true" property-ref="">

规律：凡是双向关联，必设mappedBy

多对一关联

多对一单向关联

annotation：@ManyToOne

xml：<mangy-to-one name="group" column="groupId">

一对多单向关联

annotation: @OneToMany @JoinColumn(name="groupId")   //  不加JoinColumn，会生成中间表

xml:<set name="users">

<key column="groupId"></key>

<one-to-many class="com.User" />

</set>

一对多/多对一双向关联

annotation:@OneToMany(mappedBy="group")，@ManyToOne

xml：<set name="users">

<key column="groupId"></key>

<one-to-many class="com.User" />

</set>

<many-to-one name="group" column="groupId"></many-to-one>