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Hibernate 多对多双向关联 |
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一、模型介绍 |
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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。 |
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二、实体(省略getter、setter方法) |
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public class Personnn_sx { |
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private int personid; |
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private String name; |
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private int age; |
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private Set addresses=new HashSet(); |
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public class Addressnn_sx { |
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private int addressid; |
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private String addressdetail; |
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private Set persons = new HashSet(); |
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三、表模型 |
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mysql> desc person_nn_sx; |
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+----------+--------------+------+-----+---------+----------------+ |
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| Field | Type | Null | Key | Default | Extra | |
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+----------+--------------+------+-----+---------+----------------+ |
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| personid | int(11) | NO | PRI | NULL | auto_increment | |
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| name | varchar(255) | YES | | NULL | | |
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| age | int(11) | YES | | NULL | | |
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+----------+--------------+------+-----+---------+----------------+ |
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mysql> desc address_nn_sx; |
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+---------------+--------------+------+-----+---------+----------------+ |
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| Field | Type | Null | Key | Default | Extra | |
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+---------------+--------------+------+-----+---------+----------------+ |
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| addressid | int(11) | NO | PRI | NULL | auto_increment | |
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| addressdetail | varchar(255) | YES | | NULL | | |
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+---------------+--------------+------+-----+---------+----------------+ |
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mysql> desc join_nn_sx; |
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+-----------+---------+------+-----+---------+-------+ |
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| Field | Type | Null | Key | Default | Extra | |
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+-----------+---------+------+-----+---------+-------+ |
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| addressid | int(11) | NO | PRI | | | |
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| personid | int(11) | NO | PRI | | | |
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+-----------+---------+------+-----+---------+-------+ |
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四、生成的SQL脚本 |
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ |
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CREATE TABLE `address_nn_sx` ( |
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`addressid` int(11) NOT NULL auto_increment, |
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`addressdetail` varchar(255) default NULL, |
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PRIMARY KEY (`addressid`) |
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) ENGINE=InnoDB DEFAULT CHARSET=gbk; |
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ |
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CREATE TABLE `person_nn_sx` ( |
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`personid` int(11) NOT NULL auto_increment, |
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`name` varchar(255) default NULL, |
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`age` int(11) default NULL, |
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PRIMARY KEY (`personid`) |
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) ENGINE=InnoDB DEFAULT CHARSET=gbk; |
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/* Formatted on 2007/08/22 17:59 (QP5 v5.50) */ |
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CREATE TABLE `join_nn_sx` ( |
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`addressid` int(11) NOT NULL, |
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`personid` int(11) NOT NULL, |
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PRIMARY KEY (`personid`,`addressid`), |
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KEY `FK6EBBC5EF6C600921` (`personid`), |
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KEY `FK6EBBC5EF2A92FF3D` (`addressid`), |
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CONSTRAINT `FK6EBBC5EF2A92FF3D` FOREIGN KEY (`addressid`) REFERENCES `address_nn_sx` (`addressid`), |
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CONSTRAINT `FK6EBBC5EF6C600921` FOREIGN KEY (`personid`) REFERENCES `person_nn_sx` (`personid`) |
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) ENGINE=InnoDB DEFAULT CHARSET=gbk; |
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五、映射方法 |
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<hibernate-mapping> |
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<class name="com.lavasoft.sx._n_n.Personnn_sx" table="PERSON_nn_sx"> |
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<id name="personid"> |
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<generator class="identity"/> |
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</id> |
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<property name="name"/> |
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<property name="age"/> |
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<!--映射集合属性,关联到持久化类--> |
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<!--table="join_1ntab_sx"指定了连接表的名字--> |
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<set name="addresses" |
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table="join_nn_sx" |
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cascade="all"> |
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<!--column="personid"指定连接表中关联当前实体类的列名--> |
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<key column="personid" not-null="true"/> |
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<!--column="addressid"是连接表中关联本实体的外键--> |
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<many-to-many column="addressid" |
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class="com.lavasoft.sx._n_n.Addressnn_sx"/> |
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</set> |
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</class> |
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</hibernate-mapping> |
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<hibernate-mapping> |
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<class name="com.lavasoft.sx._n_n.Addressnn_sx" |
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table="ADDRESS_nn_sx"> |
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<id name="addressid"> |
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<generator class="identity"/> |
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</id> |
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<property name="addressdetail"/> |
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<!--table="join_nn_sx"是双向多对多的连接表--> |
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<set name="persons" |
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inverse="true" |
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table="join_nn_sx"> |
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<!--column="addressid"是连接表中关联本实体的外键--> |
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<key column="addressid"/> |
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<many-to-many column="personid" |
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class="com.lavasoft.sx._n_n.Personnn_sx"/> |
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</set> |
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</class> |
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</hibernate-mapping> |
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六、测试方法 |
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public class Test_nn_sx { |
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public static void main(String[] args){ |
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Addressnn_sx add1=new Addressnn_sx(); |
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Addressnn_sx add2=new Addressnn_sx(); |
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Personnn_sx p1=new Personnn_sx(); |
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Personnn_sx p2=new Personnn_sx(); |
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add1.setAddressdetail("郑州市经三路"); |
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add2.setAddressdetail("合肥市宿州路"); |
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p1.setName("wang"); |
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p1.setAge(30); |
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p2.setName("zhang"); |
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p2.setAge(22); |
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p1.getAddresses().add(add1); |
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p1.getAddresses().add(add2); |
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p2.getAddresses().add(add2); |
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add1.getPersons().add(p1); |
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add2.getPersons().add(p1); |
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add2.getPersons().add(p2); |
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Session session= HibernateUtil.getCurrentSession(); |
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Transaction tx=session.beginTransaction(); |
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session.save(p1); |
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session.save(p2); |
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// session.saveOrUpdate(add1); |
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// session.saveOrUpdate(add2); |
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tx.commit(); |
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HibernateUtil.closeSession(); |
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} |
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} |
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七、测试结果 |
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1) :正常保存. |
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session.save(p1); |
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session.save(p2); |
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// session.saveOrUpdate(add1); |
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// session.saveOrUpdate(add2); |
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Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?) |
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Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?) |
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Hibernate: insert into ADDRESS_nn_sx (addressdetail) values (?) |
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Hibernate: insert into PERSON_nn_sx (name, age) values (?, ?) |
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?) |
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?) |
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Hibernate: insert into join_nn_sx (personid, addressid) values (?, ?) |