Hibernate关系映射2——唯一外键关联

?一、唯一外键关联映射： (每个员工只属于一个部门)

唯一外键关联生成的关系模型：
t_employee(id int pk, name varchar, departmentid int fk->t_department(id))
t_department(id int pk, name varchar)

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1、唯一外键单向关联

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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">?
???????????? <generator unique="true" column="departmentid"/>?
???? </class>?
?</hibernate-mapping>

?<!-- 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">?
???????????? <generator unique="true" column="departmentid"/>?
???? </class>?
?</hibernate-mapping>

?<!-- com.lrh.hibernate/Department.hbm.xml -->
?<hibernate-mapping>?
???? <class name="com.lrh.hibernate.Department" table="t_department">?
???????? <id name="id"><generator property-ref="department"/>?
???? </class>?
?</hibernate-mapping>
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