Hibernate关系映射1 ——主键关联映射

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主键关联生成的关系模型： (每个员工只属于一个部门)
t_employee(id int pk fk->t_department(id), name varchar)
t_department(id int pk, name varchar)

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1、主键单向关联

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实体模型：
com.lrh.hibernate.Employee(int id, String name, Department department)
com.lrh.hibernate.Department(int id, String name)

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配置文件：
?<!-- com.lrh.hibernate/Employee.hbm.xml -->
<hibernate-mapping>?
???? <class name="com.lrh.hibernate.Employee" table="t_employee">?
???????? <id name="id">?
???????????? <!-- 采用foreign生成策略，Employee的主键来源Department，forgeign会取得关联对象的标识 -->
???????????? <generator constrained="true" />?
???? </class>?
?</hibernate-mapping>?
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?<!-- com.lrh.hibernate/Department.hbm.xml -->
?<hibernate-mapping>?
???? <class name="com.lrh.hibernate.Department" table="t_department">?
???????? <id name="id"><generator table="t_employee">?
???????? <id name="id">?
???????????? <!-- 指定主键生成策略为外键 -->
???????????? <generator table="t_department">?
???????? <id name="id"><generator class="native"/></id>?
???????? <property name="name"/>?
???????? <!--
??? 需要在Department映射文件中加入<one-to-one>标签指向employee，指示hibernate如何加载employee
???默认根据主键加载
????????? -->
???????? <one-to-one name="employee"/>?
???? </class>?
?</hibernate-mapping>
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