Hibernate 多對多單向關聯

2019-11-10 18:07:13

字體：大中小

來源：轉載

供稿：網友

Hibernate 多對多單向關聯

一、模型介紹

~~多個人（Person）對應多個地址（Address）。~~

一個人可對應多個地址，一個地址也可以對應多個人。

二、實體（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;

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

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

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

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

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

mysql> desc join_nn;

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

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

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

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

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

mysql> desc person_nn;

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

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

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

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

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

四、生成的SQL腳本

/* 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>

</id>

<set name="addresses"

table="join_nn"

<many-to-many

column="addressid"

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

</set>

</class>

</hibernate-mapping>

<hibernate-mapping>

</id>

</class>

</hibernate-mapping>

六、測試方法

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("鄭州市經三路");

add2.setAddressdetail("合肥市宿州路");

add3.setAddressdetail("北京市長安路");

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、測試結果

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 PERSON_nn (name, age) values (?, ?)

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

上一篇：統計0~65535之間互不相同整數的個數

下一篇：Codeforces 100726A 或 POJ 3842

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