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                                     bigintnot 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                                     bigintnot 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 addressadd constraint FK_Reference_2foreign key (id)
            references person (id) on delete restricton update restrict;

 

三、对象模型代码

 

public class Personimplements java.io.Serializable {

  private Long id;
  private String name;
  private Address address;

 

public class Addressimplements 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">
      <columnname="id" />
      <generatorclass="identity"/>
    </id>
    <propertyname="name"type="java.lang.String">
      <columnname="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-onename="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">
      <columnname="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-->
      <generatorclass="foreign">
        <paramname="property">person</param>
      </generator>
    </id>
    <propertyname="detail"type="java.lang.String">
      <columnname="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-onename="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>
  <propertyname="connection.username">root</property>
  <propertyname="connection.url">
    jdbc:mysql://localhost:3306/mydb
  </property>
  <propertyname="dialect">
    org.hibernate.dialect.MySQLDialect
  </property>
  <propertyname="connection.password">xiaohui</property>
  <propertyname="connection.driver_class">
    com.mysql.jdbc.Driver
  </property>
  <propertyname="show_sql">true</property>
  <propertyname="format_sql">true</property>
  <mapping resource="entity/Person.hbm.xml" />
  <mapping resource="entity/Address.hbm.xml" />

</session-factory>

</hibernate-configuration>