hibernate实例简析-hibernate_one2one_ufk_1

hibernate一对一唯一外键关联映射（单向关联Person---->IdCard）

一对唯一外键关联映射是多对一关联映射的特例

可以采用<many-to-one>标签，指定多的一端的unique=true，这样就限制了多的一端的多重性为一
通过这种手段映射一对一唯一外键关联
===
IdCard idCard = new IdCard();
idCard.setCardNo("88888888888888");

Person person = new Person();
person.setName("菜10");
person.setIdCard(idCard);

//不能成功保存，因为IdCard是Transient状态
session.save(person);
---
IdCard idCard = new IdCard();
idCard.setCardNo("88888888888888");
session.save(idCard);

Person person = new Person();
person.setName("菜10");
person.setIdCard(idCard);

session.save(person);
---
Person person = (Person)session.load(Person.class, 2);
System.out.println("person.name=" + person.getName());
System.out.println("idCard.cardNo=" + person.getIdCard().getCardNo());
===
<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>
---
<hibernate-mapping>
<class name="com.bjsxt.hibernate.IdCard" table="t_idcard">
<id name="id">
<generator class="native"/>
</id>
<property name="cardNo"/>
</class>
</hibernate-mapping>
===
public class Person {

private int id;

private String name;

private IdCard idCard;
---
public class IdCard {

private int id;

private String cardNo;