hibernate一对一单向外键关联

hibernate一对一单向外键关联

一、场景

我国实行一夫一妻制,一个Husband对应一个Wife，其中Wife为主控方（悲剧啊）,即wife是属于one的一方

二、R

CREATE TABLE `wife` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(50) NOT NULL,

  PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8

CREATE TABLE `husband` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(50) NOT NULL,

  `wifeid` int(11) DEFAULT NULL,

  PRIMARY KEY (`id`),

  KEY `fk_wife` (`wifeid`),

  CONSTRAINT `fk_wife` FOREIGN KEY (`wifeid`) REFERENCES `wife` (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8

三、O

Wife

package com.linys.model;

/**
 * Wife entity. @author MyEclipse Persistence Tools
 */

public class Wife implements java.io.Serializable {

	// Fields

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String name;

	// Constructors

	/** default constructor */
	public Wife() {
	}

	/** minimal constructor */
	public Wife(String name) {
		this.name = name;
	}


	// Property accessors

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}


}

 Husband

package com.linys.model;

/**
 * Husband entity. @author MyEclipse Persistence Tools
 */

public class Husband implements java.io.Serializable {

	// Fields

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Integer id;
	private Wife wife;
	private String name;

	// Constructors

	/** default constructor */
	public Husband() {
	}

	/** minimal constructor */
	public Husband(String name) {
		this.name = name;
	}

	/** full constructor */
	public Husband(Wife wife, String name) {
		this.wife = wife;
		this.name = name;
	}

	// Property accessors

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public Wife getWife() {
		return this.wife;
	}

	public void setWife(Wife wife) {
		this.wife = wife;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

}

 

四、映射文件

Wife.hbm.xml

<?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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="com.linys.model.Wife" table="wife">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="50" not-null="true" />
        </property>
    </class>
</hibernate-mapping>

 Husband.hbm.xml

<?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">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="com.linys.model.Husband" table="husband">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        
        <property name="name" type="java.lang.String">
            <column name="name" length="50" not-null="true" />
        </property>
        
        <many-to-one name="wife" class="com.linys.model.Wife" unique="true" >
            <column name="wifeid" />
        </many-to-one>
    </class>
</hibernate-mapping>

 其中：

<many-to-one：one-to-one是many-to-one的特殊一种，只是将unique 设置成true即可

many-to-one可以看做是foreign key字段的映射，

五、测试程序

package com.linys.model;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class TestOne2OneUniFK {

	static SessionFactory sf;

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
		sf = new Configuration().configure().buildSessionFactory();

	}

	@Test
	public void testOne2OneUniFK(){
		
		Wife wife=new Wife();
		wife.setName("wife");
		
		Husband husband=new Husband();
		husband.setName("husband");
		husband.setWife(wife);
		
		Session session=sf.openSession();
		Transaction ts=session.beginTransaction();
		
		
		//插入可以
//		session.save(wife);
//		session.save(husband);
		
		//插入可以
//		session.save(husband);
//		session.save(wife);
		//插入不行
//	    session.save(husband);
		//插入可以
		session.save(wife);
		ts.commit();
		
	}
	@AfterClass
	public static void tearDownAfterClass() throws Exception {
		sf.close();
	}

}