hibernate学习笔记第7讲-一对一唯一外键关联映射one-to-one

Hibernate一对一唯一外键关联：

就是多对一的特列，把外键设置成unique为true。

采用<many-to-one name="idCard" unique="true"/>

 

 

单向：

Person.hbm.xml

<hibernate-mapping>

<class name="com.bjsxt.hibernate.Person" table="t_person">

           <id name="id">

                    <generator class="native"/>

           </id>

           <property name="name"/>

           <many-to-one name="idCard" unique="true"/>

</class>

</hibernate-mapping>

 

IdCard.hbm.xml

<hibernate-mapping>

<class name="com.bjsxt.hibernate.IdCard" table="t_idcard">

           <id name="id">

                    <generator class="native"/>

           </id>

           <property name="cardNo"/>

</class>

</hibernate-mapping>

 

双向：

需要在另一端添加<one-to-one name="person" property-ref="idCard"/>，指示hibernate如何加载关联对象，默认根据主键关联，采用外键关联需要采用property-ref="idCard"

 

 Person.hbm.xml

<hibernate-mapping>

<class name="com.bjsxt.hibernate.Person" table="t_person">

           <id name="id">

                    <generator class="native"/>

           </id>

           <property name="name"/>

           <many-to-one name="idCard" unique="true"/>

</class>

</hibernate-mapping>

 

IdCard.hbm.xml

<hibernate-mapping>

<class name="com.bjsxt.hibernate.IdCard" table="t_idcard">

           <id name="id">

                    <generator class="native"/>

           </id>

           <property name="cardNo"/>

           <one-to-one name="person" property-ref="idCard"/>

</class>

</hibernate-mapping>