Hibernate 一对一映射

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基于外键的映射（给外键加上了唯一约束）

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><!-- Generated 2016-5-11 11:46:48 by Hibernate Tools 3.5.0.Final --><hibernate-mapping>    <class name="one2one.foreign.Department" table="DEPARTMENT">        <id name="deptId" type="java.lang.Integer">            <column name="DEPT_ID" />            <generator class="native" />        </id>        <property name="deptName" type="java.lang.String">            <column name="DEPT_NAME" />        </property>        <!-- 使用 many-to-one 的方式来映射 1-1关联关系        添加unique=“true” 属性来表示为1-1关联         -->        <many-to-one name="mgr" class="one2one.foreign.Manager"        column="MGR_ID" unique="true"></many-to-one>    </class></hibernate-mapping>

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><!-- Generated 2016-5-11 11:46:48 by Hibernate Tools 3.5.0.Final --><hibernate-mapping>    <class name="one2one.foreign.Manager" table="MANAGER">        <id name="mgrId" type="java.lang.Integer">            <column name="MGR_ID" />            <generator class="native" />        </id>        <property name="mgrName" type="java.lang.String">            <column name="MGR_NAME" />        </property>                <!-- 没有外键的一端需要使用 one-to-one元素，该元素使用property -->        <one-to-one name="dept"         class="one2one.foreign.Department"        property-ref="mgr"></one-to-one>    </class></hibernate-mapping>

基于主键键的映射

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.atguigu.hibernate.one2one.primary">    <class name="Department" table="DEPARTMENTS">        <id name="deptId" type="java.lang.Integer">            <column name="DEPT_ID" />            <!-- 使用外键的方式来生成当前的主键 -->            <generator class="foreign">            <!-- property 属性指定使用当前持久化类的哪一个属性的主键作为外键 -->            <param name="property">mgr</param>            </generator>        </id>                <property name="deptName" type="java.lang.String">            <column name="DEPT_NAME" />        </property><!--  采用 foreign 主键生成器策略的一端增加 one-to-one 元素映射关联属性,其 one-to-one 节点还应增加 constrained=true 属性, 以使当前的主键上添加外键约束--><one-to-one name="mgr" class="Manager" constrained="true"></one-to-one>            </class></hibernate-mapping>

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping>    <class name="com.atguigu.hibernate.one2one.primary.Manager" table="MANAGERS">                <id name="mgrId" type="java.lang.Integer">            <column name="MGR_ID" />            <generator class="native" />        </id>                <property name="mgrName" type="java.lang.String">            <column name="MGR_NAME" />        </property>                <one-to-one name="dept"         class="com.atguigu.hibernate.one2one.primary.Department"></one-to-one>            </class>    </hibernate-mapping>

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