Hibernate 一对一外键双向关联

?一对一外键关联是一对多外键关联的特例，只是在多的一方加了个唯一性约束。?一、模型一个人对应一个地址。?/*==============================================================*/
/* DBMS name:????? MySQL 5.0??????????????????????????????????? */
/* Created on:???? 2008-12-9 0:12:54??????????????????????????? */
/*==============================================================*/
drop table if exists address;drop table if exists person;/*==============================================================*/
/* Table: address?????????????????????????????????????????????? */
/*==============================================================*/
create table address
(
?? id?????????????????? bigint not null auto_increment comment 'ID',
?? detail?????????????? varchar(120) not null comment '详细地址',
?? personid???????????? bigint comment '人的ID',
?? 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_4 foreign key (personid)
????? references person (id) on delete restrict on update restrict;??二、对象模型?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;?三、映射文件<?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>
????<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="testdb">
????<id name="id" type="java.lang.Long">
??????<column name="id" />
??????<generator class="identity" />
????</id>
????<property name="detail" type="java.lang.String">
??????<column name="detail" length="120" not-null="true">
????????<comment>详细地址</comment>
??????</column>
????</property>
????<many-to-one name="person" class="entity.Person"
??????fetch="select" unique="true">
??????<column name="personid">
????????<comment>人的ID</comment>
??????</column>
????</many-to-one>
??</class>
</hibernate-mapping>?<?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/testdb
????</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>?四、测试import org.hibernate.Transaction;

import entity.Address;
import entity.Person;

import utils.HibernateSessionFactory;

public class Test {
??public static void main(String[] args) {
????savePerson();
??}

??public static void savePerson() {
????Person person = new Person("张三");
????Address address = new Address("XX街X号");
????person.setAddress(address);
????address.setPerson(person);

????Session session = HibernateSessionFactory.getSession();
????Transaction tx = session.beginTransaction();
????session.save(person);
????tx.commit();
??}
}?运行日志：Hibernate:????
????????insert????
????????into
????????????????person
????????????????(name)????
????????values
????????????????(?)
Hibernate:????
????????insert????
????????into
????????????????testdb.address
????????????????(detail, personid)????
????????values
????????????????(?, ?)

?