传智播客Hibernate视频教程学习笔记20

基于外键的一对一关系映射

IdCard.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="domain">
<class name="IdCard" table="id_card">
<id name="id">
<generator class="native">
<param name="property">person</param>
</generator>
</id>
<property name="usefulLife" column="userful_life"></property>
<many-to-one name="person" column="person_id" unique="true" not-null="true"></many-to-one>
</class>
</hibernate-mapping>

Person.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="domain">
<class name="Person">
<id name="id">
<generator class="native"/>
</id>
<property name="name"></property>
<one-to-one name="idCard" property-ref="person"></one-to-one>
</class>
</hibernate-mapping>

这个比较符合我的思路，就是把many-to-one属性加入unique=“true”约束就可以了，再在Person中Property-ref指明参照的对象类型。