Hibernate关系映射

word
目录
1关系映射1
1.1单向关联1
1.1.1 一对一外键单向关联1
1.1.2 一对一主键单向关联5
1.1.3 一对多外键单向关联6
1.1.4 多对一外键单向关联10
1.2双向关联14
1.2.1 一对一外键双向关联14
1.2.2 一对一主键双向关联17
1.2.3 一对多外键双向关联18
1.2.4 多对多双向关联21
1关系映射1.1单向关联
1.1.1一对一外键单向关联
1、模型介绍
一个人〔Person〕对应一个地址〔Address〕。

2、实体〔无getter和setter〕
Peron
private Long oid;
private String personid;
private String name;
private Address addressfk;
Address
private Long oid;
private String addressid;
private String addressdetail;
3、表模型
以下是地址表
表1地址表
以下是人物表，其中addressid是外键引用地址表的addressid
表2人物表
4、映射文件
<hibernate-mapping package=".test.fkoo">
<class name="Address" table="address">
<id name="oid">
<generator class="native" />
</id>
<property name="addressid" unique="true" not-null="true" /> <property name="addressdetail" not-null="true" />
</class>
</hibernate-mapping>
<hibernate-mapping package=".test.fkoo">
<class name="Person" table="person">
<id name="oid">
<generator class="native" />
</id>
<property name="personid" unique="true" not-null="true" />
<property name="name" not-null="true" />
<!--用来映射关联PO column是Address在该表中的外键列名,增加unique 是唯一的-->
<!--下面的addressid只是名字而已，manytoone自动关联address方的主键不过取个有实际意义的名字让表结构更清晰-->
<many-to-one name="addressfk" column="addressid" unique="true" not-null="true"/>
</class>
</hibernate-mapping>
5、测试方法
public class Test {
public static void main(String[] args) {
Session s = HibernateUtil.getSession();
try {
s.beginTransaction();
Person p = new Person();
p.setName("xuwei");
p.setPersonid("200610801232");
Address a = new Address();
a.setAddressid("杨家冲6号");
a.setAddressdetail("某某市大安区");
p.setAddressfk(a);
s.save(a);
s.save(p);
s.getTransaction().mit();
} catch (HibernateException e) {
e.printStackTrace();
s.getTransaction().rollback();
} finally {
s.close();
}
}
}
6、测试结果
a、s.save(a);s.save(p);
正常保存
b、s.save(p);s.save(a);
异常发生，异常信息：
not-null property references a null or transient value c、s.save(a)
能够插入，但信息不全，只插入一条记录。

d、s.save(p)
异常发生，异常信息：
not-null property references a null or transient value
1.1.2一对一主键单向关联
1、要改的地方只有一个就是
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"/hibernate-mapping-3.0.dtd">
<hibernate-mapping package=".test.pkoo">
<class name="Person" table="person">
<id name="oid" column="oid">
<!--基于主键关联时，主键生成策略是foreign，明确根据关联类生成主键-->
<generator class="foreign">
<!--关联持久化类的属性名-->
<param name="property">addressfk</param>
</generator>
</id>
<property name="personid" unique="true" not-null="true" />
<property name="name" not-null="true" />
<!--用于映射1-1关联-->
<one-to-one name="addressfk" constrained="true" />
</class>
</hibernate-mapping>
2、测试结果
a、s.save(a);s.save(p);
正常保存，推荐方式，先插入父表，再插入子表
b、s.save(p);s.save(a);
正常保存，也是先插入父表，再插入子表
c、s.save(a)
能够插入，但信息不全，只插入一条记录。

d、s.save(p)
正常保存，而且插入两条记录。

1.1.3一对多外键单向关联
1、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。

2、实体
Address
private Long aid;
private String addressid;
private String addressdetail;
Person
private Long pid;
private String personid;
private String name;
private Set<Address> addresses = new HashSet<Address>(); 3、表模型
以下是地址表此表是多的一方pid为外键
表3地址表
以下是人物表
表4人物表
4、映射文件
<hibernate-mapping package=".test.fkom">
<class name="Address" table="address">
<id name="aid">
<generator class="native" />
</id>
<property name="addressid" unique="true" not-null="true" /> <property name="addressdetail" not-null="true" />
</class>
</hibernate-mapping>
<hibernate-mapping package=".test.fkom">
<class name="Person" table="person">
<id name="pid">
<generator class="native" />
</id>
<property name="personid" unique="true" not-null="true" />
<property name="name" not-null="true" />
<!--
映射集合属性，关联到持久化类,inverse="false"表示主控端在Person表端，lazy="false"表示不采用延迟加载
-->
<set name="addresses" table="address" cascade="all" >
<!--确定关联的外键列-->
<key column="pid" />
<!--用以映射到关联类属性-->
<one-to-many class="Address" />
</set>
</class>
</hibernate-mapping>
5、测试方法
public class Test {
public static void main(String[] args) {
Session s = HibernateUtil.getSession(); try {
s.beginTransaction();
Person p = new Person();
Address a1 = new Address();
Address a2 = new Address();
a1.setAddressid("杨家1号");
a1.setAddressdetail("某某市大安区");
a2.setAddressid("杨家2号");
a2.setAddressdetail("某某市大安区"); p.setName("xuwei");
p.setPersonid("1");
p.getAddresses().add(a1);
p.getAddresses().add(a2);
s.save(a1);
s.save(a2);
s.save(p);
s.getTransaction().mit();
} catch (HibernateException e) {
e.printStackTrace();
s.getTransaction().rollback();
} finally {
s.close();
}
}
6、测试结果
a、s.save(a1);s.save(a2); s.save(p);
正常保存，信息：
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
Hibernate: insert into person (personid, name) values (?, ?)
Hibernate: update address set pid=? where aid=?
Hibernate: update address set pid=? where aid=?
b、s.save(p)
正常保存，同上。

c、s.save(a1);s.save(a2);
正常保存，但信息不全：
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
1.1.4多对一外键单向关联
1、模型介绍
多个人〔Person〕对应一个地址〔Address〕。

2、实体
Address
private Long oid;
private String addressid;
private String addressdetail;
Person
private Long oid;
private String personid;
private String name;
private Address addressfk;
3、表模型
以下是地址表
表5地址表
以下是人物表，多个人对应一个地址：
表6人物表
4、映射文件
<hibernate-mapping package=".test.fkmo">
<class name="Person" table="person">
<id name="pid">
<generator class="native" />
</id>
<property name="personid" unique="true" not-null="true" /> <property name="name" not-null="true" />
<!--用来映射关联PO column是Address在该表中的外键列名--> <many-to-one name="addressfk" column="addressid" />
</class>
</hibernate-mapping>
5、测试方法
Person p1 = new Person();
Person p2 = new Person();
Address a = new Address();
p1.setName("xuwei");
p1.setPersonid("001");
p2.setName("weixu");
p2.setPersonid("002");
a.setAddressid("杨家1号");
a.setAddressdetail("某某市大安区");
p1.setAddressfk(a);
p2.setAddressfk(a);
s.save(a);
s.save(p1);
s.save(p2);
6、测试结果
a、s.save(a); s.save(p1); s.save(p2);
正常保存，信息为：
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
b、s.save(p1); s.save(p2); s.save(a);
正常保存，信息：
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
Hibernate: insert into address (addressid, addressdetail) values (?, ?)
Hibernate: update person set personid=?, name=?, addressid=? where pid=?
Hibernate: update person set personid=?, name=?, addressid=? where pid=?
c、s.save(p1); s.save(p2);
发生异常，异常信息：
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
Hibernate: insert into person (personid, name, addressid) values (?, ?, ?)
org.hibernate.TransientObjectException: object references an unsaved transient instance
1.2双向关联
1.2.1一对一外键双向关联
1、模型介绍
同一对一单向关联
2、实体
Person
private Long oid;
private String name;
private Address addressfk;
Address
private Long oid;
private String addressdetail;
private Person personfk;
3、表模型
表7address表
表8person表
3、映射文件
<hibernate-mapping package=".test.eachoo">
<class name="Address" table="address">
<id name="oid">
<generator class="native" />
</id>
<property name="addressdetail" not-null="true" />
<!--外键方，外键一列名为personid，自动引用Person的oid作为外键--> <many-to-one name="personfk" column="personid" unique="true"
not-null="true"></many-to-one>
</class>
</hibernate-mapping>
<hibernate-mapping package=".test.eachoo">
<class name="Person" table="person">
<id name="oid">
<generator class="native" />
</id>
<property name="name" not-null="true" />
<!-- 主表方cascade=〞all〞表示级联更新和删除可以添加属性property-ref="personfk",其中personfk为Address.hbm.xml中的many-to-one的name-->
<one-to-one name="addressfk" cascade="all" ></one-to-one>
</class>
</hibernate-mapping>
4、测试
Person p = new Person();
p.setName("xuwei");
Address a = new Address();
a.setAddressdetail("某某市大安区");
p.setAddressfk(a);
a.setPersonfk(p);
s.save(p);
5、测试结果
a、p.setAddressfk(a);a.setPersonfk(p);s.save(p);
正常保存，信息如下：
Hibernate: insert into person (name) values (?)
Hibernate: insert into address (addressdetail, personid) values (?, ?)
b、p.setAddressfk(a);a.setPersonfk(p);s.save(a);
异常抛出，信息如下：
not-null property references a null or transient value
1.2.2一对一主键双向关联
1、需要改动的地方就是
<hibernate-mapping package=".test.eachpkoo">
<class name="Address" table="address">
<id name="oid">
<generator class="foreign">
<param name="property">personfk</param>
</generator>
</id>
<property name="addressdetail" not-null="true" />
<!-- 表示在address表存在一个外键约束，外键参考相关联的表person -->
<one-to-one name="personfk" constrained="true" />
</class>
</hibernate-mapping>
1.2.3一对多外键双向关联
1、模型介绍
一个人〔Person〕对于多个地址〔Address〕
2、实体
Address
private Long oid;
private String addressdetail;
private Person personfk;
Person
private Long oid;
private String name;
private Set<Address> addresses = new HashSet<Address>();
3、表模型
表9address表
表10person表
4、映射文件
<hibernate-mapping package=".test.eachfkom">
<class name="Address" table="address">
<id name="oid">
<generator class="native" />
</id>
<property name="addressdetail" not-null="true" />
<!--映射关联属性，column属性指定外键列名-->
<many-to-one name="personfk" class="Person" fetch="select" cascade="save-update" column="fid" />
</class>
</hibernate-mapping>
<hibernate-mapping package=".test.eachfkom">
<class name="Person" table="person">
<id name="oid">
<generator class="native" />
</id>
<property name="name" not-null="true" />
<!--映射集合属性，关联到持久化类-->
<set name="addresses" inverse="true" cascade="all">
<!--column用于指定外键列名-->
<key column="fid" not-null="true" /> <!--映射关联类-->
<one-to-many class="Address" />
</set>
</class>
</hibernate-mapping>
5、测试方法
s.beginTransaction();
Person p = new Person();
Address a1 = new Address();
Address a2 = new Address();
a1.setAddressdetail("某某市大安区"); a2.setAddressdetail("某某市大安区"); p.setName("xuwei");
p.getAddresses().add(a1);
p.getAddresses().add(a2);
a1.setPersonfk(p);
a2.setPersonfk(p);
s.save(p);
s.saveOrUpdate(a1);
s.saveOrUpdate(a2);
s.getTransaction().mit();
6、测试结果
s.save(p);
s.saveOrUpdate(a1);
s.saveOrUpdate(a2);
或者
s.save(p);
或者
s.saveOrUpdate(a1);
s.saveOrUpdate(a2);
均能正常保存
1.2.4多对多双向关联
1、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。

2、实体
Address
private Long oid;
private String addressdetail;
private Set<Person> persons=new HashSet<Person>();
Person
private Long oid;
private String name;
private Set<Address> addresses = new HashSet<Address>();
3、表模型
表11Address表
表12Person表
表13中间关系表
4、映射文件
<hibernate-mapping package=".test.eachmm">
<class name="Person" table="person">
<id name="oid">
<generator class="native" />
</id>
<property name="name" not-null="true" />
<!--映射集合属性，关联到持久化类-->
<!--table="third"指定了连接表的名字-->
<set name="addresses" table="third_mid" cascade="all"> <!--column="personid"指定连接表中关联当前实体类的列名--> <key column="personid" not-null="true" />
<!--column="addressid"是连接表中关联本实体的外键-->
<many-to-many column="addressid" class="Address" />
</set>
</class>
</hibernate-mapping>
<hibernate-mapping package=".test.eachmm">
<class name="Address" table="address">
<id name="oid">
<generator class="native" />
</id>
<property name="addressdetail" not-null="true" />
<!--table="third"是双向多对多的连接表-->
<set name="persons" inverse="true" table="third_mid">
<!--column="addressid"是连接表中关联本实体的外键-->
<key column="addressid" />
<many-to-many column="personid" class="Person" />
</set>
</class>
</hibernate-mapping>
5、测试方法
s.beginTransaction();
Person p1= new Person();
Person p2= new Person();
Address a1 = new Address();
Address a2 = new Address();
a1.setAddressdetail("某某市大安区"); a2.setAddressdetail("内江市威远县"); p1.setName("xuwei");
p2.setName("weixu");
p1.getAddresses().add(a1);
p1.getAddresses().add(a2);
p2.getAddresses().add(a2);
a1.getPersons().add(p1);
a2.getPersons().add(p1);
a2.getPersons().add(p2);
s.save(p1);
s.save(p2);
// s.saveOrUpdate(a1);
// s.saveOrUpdate(a2);
s.getTransaction().mit();
6、测试结果
a、s.save(p1); s.save(p2);
正常保存，信息：
Hibernate: insert into person (name) values (?)
Hibernate: insert into address (addressdetail) values (?) Hibernate: insert into address (addressdetail) values (?) Hibernate: insert into person (name) values (?)
Hibernate: insert into third_mid (personid, addressid) values (?, ?) Hibernate: insert into third_mid (personid, addressid) values (?, ?) Hibernate: insert into third_mid (personid, addressid) values (?, ?)
徐伟
联系方法：无。