Hibernate 多对多单向关联

Hibernate 多对多单向关联

 

 

一、模型介绍

多个人（Person）对应多个地址（Address）。

一个人可对应多个地址，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

 

<hibernate-mapping>

    <class name="com.lavasoft.dx._n_n.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.lavasoft.dx._n_n.Addressnn"/>

        </set>

    </class>

</hibernate-mapping>

 

<hibernate-mapping>

    <class name="com.lavasoft.dx._n_n.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("郑州市经三路");

        add2.setAddressdetail("合肥市宿州路");

        add3.setAddressdetail("北京市长安路");

        p1.setName("wang");

        p1.setAge(30);

        p2.setName("lee");

        p2.setAge(50);

 

        p1.getAddresses().add(add1);

        p1.getAddresses().add(add2);

        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();

    }

}

 

七、测试结果

 

1) :正常保存.

        session.save(add1);

        session.save(add2);

        session.save(add3);

        session.save(p1);

        session.save(p2);

 

Hibernate: insert into ADDRESS_nn (addressdetail) values (?)

Hibernate: insert into ADDRESS_nn (addressdetail) values (?)

Hibernate: insert into ADDRESS_nn (addressdetail) values (?)

Hibernate: insert into PERSON_nn (name, age) values (?, ?)

Hibernate: insert into PERSON_nn (name, age) values (?, ?)

Hibernate: insert into join_nn (personid, addressid) values (?, ?)

Hibernate: insert into join_nn (personid, addressid) values (?, ?)

Hibernate: insert into join_nn (personid, addressid) values (?, ?)

Hibernate: insert into join_nn (personid, addressid) values (?, ?)