Hibernate 一对一主键单向关联
1-1的关联可以基于主键关联，但基于主键关联的持久化类不能拥有自己的主键生成策略，它的主键由关联类负责生成。另外，另外，增加one-to-one元素来关联属性，必须为one-to-one元素增加constrained="true"属性，表明该类主键由关联类生成。
一、模型介绍
一个人（Person）对应一个地址（Address）。
二、实体（省略getter、setter方法）
publicclassPerson11pk{
privateintpersonid;
privateStringname;
privateintage;
privateAddress11pkaddress11pk;
publicclassAddress11pk{
privateintaddressid;
privateStringaddressdetail;
三、表模型
mysql>descaddress_11pk;
+---------------+--------------+------+-----+---------+----------------+
|Field|Type|Null|Key|Default|Extra|
+---------------+--------------+------+-----+---------+----------------+
|addressid|int(11)|NO|PRI|NULL|auto_increment|
|addressdetail|varchar(255)|YES||NULL||
+---------------+--------------+------+-----+---------+----------------+
mysql>descperson_11pk;
+----------+--------------+------+-----+---------+-------+
|Field|Type|Null|Key|Default|Extra|
+----------+--------------+------+-----+---------+-------+
|personid|int(11)|NO|PRI|||
|name|varchar(255)|YES||NULL||
|age|int(11)|YES||NULL||
+----------+--------------+------+-----+---------+-------+
四、生成的SQL脚本
/*Formattedon2007/08/2214:40(QP5v5.50)*/
CREATETABLE`address_11pk`(
`addressid`int(11)NOTNULLauto_increment,
`addressdetail`varchar(255)defaultNULL,
PRIMARYKEY(`addressid`)
)ENGINE=InnoDBAUTO_INCREMENT=2DEFAULTCHARSET=gbk;
/*Formattedon2007/08/2214:41(QP5v5.50)*/
CREATETABLE`person_11pk`(
`presonid`int(11)NOTNULL,
`name`varchar(255)defaultNULL,
`age`int(11)defaultNULL,
PRIMARYKEY(`presonid`),
KEY`FK68A882C591BB393E`(`presonid`),
CONSTRAINT`FK68A882C591BB393E`FOREIGNKEY(`presonid`)REFERENCES`address_11pk`(`addressid`)
)ENGINE=InnoDBDEFAULTCHARSET=gbk;
五、映射方法：在Person中配置id生成策略为：
<idname="personid">
<!--基于主键关联时，主键生成策略是foreign，表明根据关联类生成主键-->
<generatorclass="foreign">
<!--关联持久化类的属性名-->
<paramname="property">address11pk</param>
</generator>
</id>
......
<!--用于映射1-1关联-->
<one-to-onename="address11pk"constrained="true"/>
<hibernate-mapping>
<classname="com.lavasoft.dx._1_1_pk.Person11pk"table="PERSON_11pk">
<idname="personid"column="presonid">
<!--基于主键关联时，主键生成策略是foreign，表明根据关联类生成主键-->
<generatorclass="foreign">
<!--关联持久化类的属性名-->
<paramname="property">address11pk</param>
</generator>
</id>
<propertyname="name"/>
<propertyname="age"/>
<!--用于映射1-1关联-->
<one-to-onename="address11pk"constrained="true"/>
</class>
</hibernate-mapping>
<hibernate-mapping>
<classname="com.lavasoft.dx._1_1_pk.Address11pk"table="ADDRESS_11pk">
<idname="addressid">
<generatorclass="identity"/>
</id>
<propertyname="addressdetail"/>
</class>
</hibernate-mapping>
六、测试方法
publicclassTest_11pk{
publicstaticvoidmain(String[]args){
Person11pkp1=newPerson11pk();
p1.setAge(21);
p1.setName("p1");
Address11pkadd1=newAddress11pk();
add1.setAddressdetail("郑州市经三路");
p1.setAddress11pk(add1);
Sessionsession=HibernateUtil.getCurrentSession();
Transactiontx=session.beginTransaction();
session.save(add1);
session.save(p1);
tx.commit();
HibernateUtil.closeSession();
}
}
七、测试结果
1):正常保存.推荐这么干!
session.save(add1);
session.save(p1);
Hibernate:insertintoADDRESS_11fk(addressdetail)values(?)
Hibernate:insertintoPERSON_11fk(name,age,addressId)values(?,?,?)
2):正常保存.
session.save(p1);
session.save(add1);
Hibernate:insertintoPERSON_11fk(name,age,addressId)values(?,?,?)
Hibernate:insertintoADDRESS_11fk(addressdetail)values(?)
Hibernate:updatePERSON_11fksetname=?,age=?,addressId=?wherepersonid=?
3):正常保存.
//session.save(p1);
session.save(add1);
Hibernate:insertintoADDRESS_11fk(addressdetail)values(?)
4):发生异常,不能保存.
session.save(p1);
//session.save(add1);
Hibernate:insertintoPERSON_11fk(name,age,addressId)values(?,?,?)
Exceptioninthread"main"org.hibernate.TransientObjectException:com.lavasoft.dx._1_1_fk.Address11fk
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