Hibernate关联之 多对多单向关联

Hibernate 多对多单向关联

 

一、模型介绍

 

 

一个人可以对应多个地址，一个地址也可以对应多个人。

二、实体（省略getter、setter方法）

 

public class Personnn {

    private int personid;

    private String name;

    private int age;

    private Set addresses=new HashSet();

 

public class Addressnn {

    private int addressid;

    private String addressdetail;

 

三、表模型

 

mysql> desc person_nn;

+----------+--------------+------+-----+---------+----------------+

| Field    | Type         | Null | Key | Default | Extra          |

+----------+--------------+------+-----+---------+----------------+

| personid | int(11)      | NO   | PRI | NULL    | auto_increment |

| name     | varchar(255) | YES  |     | NULL    |                |

| age      | int(11)      | YES  |     | NULL    |                |

+----------+--------------+------+-----+---------+----------------+

 

mysql> desc join_nn;

+-----------+---------+------+-----+---------+-------+

| Field     | Type    | Null | Key | Default | Extra |

+-----------+---------+------+-----+---------+-------+

| personid  | int(11) | NO   | PRI |         |       |

| addressid | int(11) | NO   | PRI |         |       |

+-----------+---------+------+-----+---------+-------+

 

mysql> desc person_nn;

+----------+--------------+------+-----+---------+----------------+

| 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 11:13 (QP5 v5.50) */

CREATE TABLE `address_nn` (

  `addressid` int(11) NOT NULL auto_increment,

  `addressdetail` varchar(255) default NULL,

  PRIMARY KEY  (`addressid`)

) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=gbk;

 

/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */

CREATE TABLE `join_nn` (

  `personid` int(11) NOT NULL,

  `addressid` int(11) NOT NULL,

  PRIMARY KEY  (`personid`,`addressid`),

  KEY `FKAAB98CF5E008E752` (`personid`),

  KEY `FKAAB98CF5239F6A16` (`addressid`),

  CONSTRAINT `FKAAB98CF5239F6A16` FOREIGN KEY (`addressid`) REFERENCES `address_nn` (`addressid`),

  CONSTRAINT `FKAAB98CF5E008E752` FOREIGN KEY (`personid`) REFERENCES `person_nn` (`personid`)

) ENGINE=InnoDB DEFAULT CHARSET=gbk;

 

/* Formatted on 2007/08/21 11:14 (QP5 v5.50) */

CREATE TABLE `person_nn` (

  `personid` int(11) NOT NULL auto_increment,

  `name` varchar(255) default NULL,

  `age` int(11) default NULL,

  PRIMARY KEY  (`personid`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=gbk;

 

五、映射方法

 

ManyToManyPerson.hbm.xml

<hibernate-mapping>     <class name="com.bean.Personnn" table="PERSON_nn">         <id name="personid">             <generator class="identity"/>         </id>         <property name="name"/>        <property name="age"/>        <!--映射集合属性，join_1ntab是连接表表名-->        <set name="addresses" table="join_nn" >            <!--“column="personid"”确定PERSON_1ntab表关联到连接表的外键列名-->            <key column="personid"/>            <!--“column="addressid"”关联PERSON_1ntab表的Address1ntab对象的id在连接表中的列名-->            <many-to-many column="addressid" class="com.bean.Addressnn"/>        </set>    </class></hibernate-mapping>

ManyToManyAddress.hbm.xml

<hibernate-mapping>     <class name="com.bean.Addressnn" table="ADDRESS_nn">        <id name="addressid">            <generator class="identity"/>        </id>        <property name="addressdetail"/>    </class></hibernate-mapping>

 

六、测试方法

 

 

public class Test_nn {public static void main(String[] args){         Addressnn add1=new Addressnn();        Addressnn add2=new Addressnn();        Addressnn add3=new Addressnn();        Personnn p1=new Personnn();        Personnn p2=new Personnn();        add1.setAddressdetail("天津市南开区");        add2.setAddressdetail("大连市");        add3.setAddressdetail("哈尔滨市群力");        p1.setName("liu");        p1.setAge(30);        p2.setName("lee");        p2.setAge(29);        p1.getAddresses().add(add1);        p1.getAddresses().add(add3);        p2.getAddresses().add(add2);        p2.getAddresses().add(add3);         Session session= HibernateUtil.getCurrentSession();        Transaction tx=session.beginTransaction();        session.save(add1);        session.save(add2);        session.save(add3);        session.save(p1);        session.save(p2);        tx.commit();        HibernateUtil.closeSession();    } }