Hibernate 一对一主键双向关联
Hibernate 一对一主键双向关联一对一主键映射在一对一映射中还算是最为常用的。
一、模型
一个人Person 对应一个地址Address。
二、数据模型和对象模型图
导出建表SQL如下：
/*==============================================================*/
/* DBMS name: MySQL 5.0 */
/* Created on: 2008-12-8 23:05:32 */
/*==============================================================*/
drop table if exists address;
drop table if exists person;
/*==============================================================*/
/* Table: address */
/*==============================================================*/
create table address
(
id bigint not null comment 'ID',
detail varchar(120) not null comment '详细地址',
primary key (id)
)
type = InnoDB;
alter table address comment '地址';
/*==============================================================*/
/* Table: person */
/*==============================================================*/
create table person
(
id bigint not null auto_increment comment 'ID',
name varchar(24) not null comment '姓名',
primary key (id)
)
type = InnoDB;
alter table person comment '人';
alter table address add constraint FK_Reference_2 foreign key (id)
references person (id) on delete restrict on update restrict;
三、对象模型代码
public class Person implements java.io.Serializable {
private Long id;
private String name;
private Address address;
public class Address implements java.io.Serializable {
private Long id;
private Person person;
private String detail;
四、映射代码
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="entity.Person" table="person">
<id name="id" type="java.lang.Long">
<column name="id" />
<generator class="identity" />
</id>
<property name="name" type="java.lang.String">
<column name="name" length="24" not-null="true">
<comment>姓名</comment>
</column>
</property>
<!-- cascade="all"：在保存person对象的时候，级联保存person对象关联的address对象 -->
<one-to-one name="address" cascade="all" />
</class>
</hibernate-mapping>
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="entity.Address" table="address" catalog="mydb">
<id name="id" type="java.lang.Long">
<column name="id" />
<!-- class="foreign": 一对一主键映射中，使用另外一个相关联的对象的标识符 -->
<generator class="foreign">
<param name="property">person</param>
</generator>
</id>
<property name="detail" type="java.lang.String">
<column name="detail" length="120" not-null="true">
<comment>详细地址</comment>
</column>
</property>
<!-- 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="person" constrained="true" />
</class>
</hibernate-mapping>
五、Hibernate配置
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<property name="connection.username">root</property>
<property name="connection.url">
jdbc:mysql://localhost:3306/mydb
</property>
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="connection.password">xiaohui</property>
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<mapping resource="entity/Person.hbm.xml" />
<mapping resource="entity/Address.hbm.xml" />
</session-factory>
</hibernate-configuration>
测试很简单就不写了。
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