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Hibernate关联之 一对多外键单向关联

2015-08-28 14:55 302 查看
Hibernate 一对多外键单向关联
这种情况很少见，但Hibernate同样允许采用连接表关联1-1.有连接表的1-1同样只需要将N-1的many-to-one元素增加unique="true"属性即可。
一、模型介绍
一个人（Person）对应多个地址（Address），比如家庭地址、公司地址。
二、实体（省略getter、setter方法）
public class Person1nfk implements Serializable {
private int personid;
private String name;
private int age;
private Set addresses=new HashSet();
public class Address1nfk implements Serializable {
private int addressid;
private String addressdetail;
三、表模型
mysql> desc address_1nfk;
+---------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+----------------+
| addressid | int(11) | NO | PRI | NULL | auto_increment |
| addressdetail | varchar(255) | YES | | NULL | |
| personid | int(11) | YES | MUL | NULL | |
+---------------+--------------+------+-----+---------+----------------+
mysql> desc person_1nfk;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| personid | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(255) | YES | | NULL | |
| age | int(11) | YES | | NULL | |
+----------+--------------+------+-----+---------+----------------+
四、生成的SQL脚本
/* Formatted on 2007/08/21 10:06 (QP5 v5.50) */
CREATE TABLE `address_1nfk` (
`addressid` int(11) NOT NULL auto_increment,
`addressdetail` varchar(255) default NULL,
`addresses` int(11) default NULL,
PRIMARY KEY (`addressid`),
KEY `FK9B93456DC08D1667` (`addresses`),
CONSTRAINT `FK9B93456DC08D1667` FOREIGN KEY (`addresses`) REFERENCES `person_1nfk` (`personid`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=gbk;
/* Formatted on 2007/08/21 10:07 (QP5 v5.50) */
CREATE TABLE `person_1nfk` (
`personid` int(11) NOT NULL auto_increment,
`name` varchar(255) default NULL,
`age` int(11) default NULL,
PRIMARY KEY (`personid`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=gbk;
五、映射方法：在实体类Person里面添加Address的集合，即可形成一对多关系。
OneToManyFKPerson.hbm.xml

<hibernate-mapping>

<class name="com.bean.Person1nfk" table="PERSON_1nfk">

<id name="personid">

<generator class="identity"/>

</id>

<property name="name"/>

<property name="age"/>

<!--映射集合属性，关联到持久化类,inverse="false"表示主控端在Person1nfk端，lazy="false"表示不采用延迟加载-->
<set name="addresses"  table="ADDRESS_1nfk" inverse="true" cascade="all" >

<!--确定关联的外键列-->
<key column="personid"/>

<!--用以映射到关联类属性-->
<one-to-many  class="com.bean.Address1nfk"/>

</set>

</class>

</hibernate-mapping>


OneToManyFKAddress.hbm.xml

<hibernate-mapping>

<class name="com.bean.Address1nfk" table="ADDRESS_1nfk">

<id name="addressid">

<generator class="identity"/>

</id>

<property name="addressdetail"/>

</class>

</hibernate-mapping>


[align=left]六、测试方法[/align]
[align=left] [/align]
public class Test_1nfk {

public static void main(String[] args){

Person1nfk p=new Person1nfk();
p.setName("lee");
p.setAge(30);

Address1nfk add1=new Address1nfk();
Address1nfk add2=new Address1nfk();

add1.setAddressdetail("大连市");
add2.setAddressdetail("哈尔滨市群力");

p.getAddresses().add(add1);
p.getAddresses().add(add2);

Session session= HibernateUtil.getCurrentSession();
Transaction tx=session.beginTransaction();
session.save(add1);
session.save(add2);
session.save(p);
tx.commit();
HibernateUtil.closeSession();

}

}
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