08hibernate_one2one_ufk_2

hibernate一对一唯一外键关联映射（双向关联Person<---->IdCard）
public class Person {

    private int id;
    
    private String name;
    
    private IdCard idCard; 
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public class IdCard {
    
    private int id;
    
    private String cardNo;
    
    private Person person;    
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<hibernate-mapping>
    <class name="com.bjsxt.hibernate.IdCard" table="t_idcard">
        <id name="id">
            <generator class="native"/>
        </id>
        <property name="cardNo"/>
        
        <!--
        一对一唯一外键关联双向，需要在（idcard）端，添加one2one标签，
        指示hibernate如何加载其关联对象，默认根据主键加载person，
        此时，在外键关联映射中，因为两个实体采用的是person的外键维护的关系，
        所以不能指定主键加载person，而要根据person的外键idCard加载，所以采用如下映射方式
        -->
        <one-to-one name="person" property-ref="idCard"/>
    </class>
</hibernate-mapping>


<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>
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public void testSave() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();
            
            IdCard idCard = new IdCard();
            idCard.setCardNo("88888888888888");
            session.save(idCard);
            
            Person person = new Person();
            person.setName("菜10");
            person.setIdCard(idCard);
            
            session.save(person);
            
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }            
    public void testLoad1() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();
            
            Person person = (Person)session.load(Person.class, 2);
            System.out.println("person.name=" + person.getName());
            System.out.println("idCard.cardNo=" + person.getIdCard().getCardNo());
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }        
    
    public void testLoad2() {
        Session session = null;
        try {
            session = HibernateUtils.getSession();
            session.beginTransaction();
            
            IdCard idCard = (IdCard)session.load(IdCard.class, 1);
            System.out.println("idcard.cardNo=" + idCard.getCardNo());
            System.out.println("idcard.person.name=" + idCard.getPerson().getName());
            
            session.getTransaction().commit();
        }catch(Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally {
            HibernateUtils.closeSession(session);
        }
    }    
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一对一唯一外键关联双向，需要在另一端（idcard），添加<one-to-one>标签，指示hibernate如何加载
其关联对象，默认根据主键加载person，外键关联映射中，因为两个实体采用的是person的外键维护的关系，
所以不能指定主键加载person，而要根据person的外键加载，所以采用如下映射方式：
<one-to-one name="person" property-ref="idCard"/>

由于没有改变数据库结构，不象many-to-one会往数据库中加字段，所以，我们还是使用的07hibernate_one2one_ufk_1，而没有去重新导入一个新的表和数据库08hibernate_one2one_ufk_2

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testLoad1：
Hibernate: select person0_.id as id1_0_, person0_.name as name1_0_, person0_.idCard as idCard1_0_ from t_person person0_ where person0_.id=?
person.name=菜10
Hibernate: select idcard0_.id as id0_1_, idcard0_.cardNo as cardNo0_1_, person1_.id as id1_0_, person1_.name as name1_0_, person1_.idCard as idCard1_0_ from t_idcard idcard0_ left outer join t_person person1_ on idcard0_.id=person1_.idCard where idcard0_.id=?
Hibernate: select person0_.id as id1_0_, person0_.name as name1_0_, person0_.idCard as idCard1_0_ from t_person person0_ where person0_.idCard=?
idCard.cardNo=88888888888888

testLoad2：
Hibernate: select idcard0_.id as id0_1_, idcard0_.cardNo as cardNo0_1_, person1_.id as id1_0_, person1_.name as name1_0_, person1_.idCard as idCard1_0_ from t_idcard idcard0_ left outer join t_person person1_ on idcard0_.id=person1_.idCard where idcard0_.id=?
idcard.cardNo=88888888888888
idcard.person.name=菜10