对《深入浅出hibernate》一书中one-to-one主键关联映射疑惑

这两天在研究hibernate,发现<<深入浅出hibernate>>一书挺好，清晰易懂，只是在看到one to one 主键关联映射的地方，有些疑惑。

 

关系模型是这样的，很简单，如下：

 

T_Person

id  number(11) <pk,fk>

name varchar2(50)

age number(3)

.....

 

 

T_PASSPORT

id number(11) <pk>,

serial varchar2(20),

expiry number(11)

 

如上，T_Person的id即是主键又是外键，引用T_PASSPORT的主键字段id.并且它们是一对一的关系。

 

对应的实体类如下：

 

 

TPerson implents Serializable

+TPerson

id:Integer

age:Integer

name:String

passport:TPassport

 

 

 

TPassport implents Serializable

+Tpassport

id:Integer

serial:String

expiry:Integer

person:Tperson

 

实体关系如上，它们建立了双向一对一关系，具体映射文件如下：

 

<?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="com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPerson" table="T_PERSON">
		<id name="id" column="id" type="java.lang.Integer">
		<generator class="sequence">
				<param name="sequence">person_seq</param>
			</generator>
		</id>
		<property name="name" type="string" column="name"></property>
		<property name="age" type="java.lang.Integer" column="age"></property>
		<one-to-one name="passport"  class="com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPassport"
					cascade="all"
					outer-join="true"/>
	</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="com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPassport" table="T_PASSPORT">
		<id name="id" column="id" type="java.lang.Integer">
			
			<generator class="foreign">
				<param name="property">person</param>
			</generator>
			
		</id>
		<one-to-one name="person"
					class="com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPerson"
					constrained="true"
					></one-to-one>
		<property name="serial" type="string" column="SERIAL"></property>
		<property name="expiry" type="java.lang.Integer" column="EXPIRY"></property>
	</class>
</hibernate-mapping>

 

 

    测试代码如下：

 

 

package com.alcatel.cn.hibernate.ORMapping.onetoone.test;

import org.hibernate.Session;
import org.hibernate.Transaction;

import com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPassport;
import com.alcatel.cn.hibernate.ORMapping.onetoone.pojo.TPerson;
import com.alcatel.cn.hibernate.common.HibernateUtil;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Session s=HibernateUtil.currentSession();
		
		TPerson p=new TPerson();
		p.setAge(20);
		p.setName("Sunrui");
		
		TPassport passport=new TPassport();
		passport.setSerial("PCN759386");
		passport.setExpiry(new Integer(2));
		
		//相互设置关联
		passport.setPerson(p);
		p.setPassport(passport);
		
		
		try{
			Transaction tx=s.beginTransaction();
			
			s.save(p);//注意：这里只对Person进行保存
			tx.commit();
			
			TPassport pp=(TPassport)s.load(TPassport.class, new Integer(5));
			System.out.println("Passport Serial ==>"+pp.getSerial());
			System.out.println("Person name==>"+pp.getPerson().getName());
		}catch(Exception e){
			e.printStackTrace();
		}
	}

}

 

运行，出现如下异常：

 

Hibernate: select person_seq.nextval from dual
Hibernate: insert into T_PERSON (name, age, id) values (?, ?, ?)
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:249)
	at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:92)
	at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:87)
	at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:218)
	at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2159)
	at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2595)
	at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:51)
	at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:248)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:232)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:139)
	at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:297)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
	at com.alcatel.cn.hibernate.ORMapping.onetoone.test.Test.main(Test.java:36)
Caused by: java.sql.BatchUpdateException: ORA-02291: integrity constraint (HIBERNATE.FK_PASSPORT) violated - parent key not found

 

 

 

仔细把自己的代码与书中的实例对照了下，发现没有任何差错，但确确实实发生异常了。仔细分析了下，这个异常是违反了约束性，第一想到的是违反了外键约束，看看日志(阴影部分)，它确实是先往T_Person表里插入记录，当然找不到对应的T_Passport的id，违反了外键约束。

 

我尝试了把Person.hbm.xml与Passport.hbm.xml中配置方式互换，即让Passport.hbm.xml维护主键生成，然后Person.hbm.xml配置外键生成方式。运行完好。

 

这里，我从不怀疑<<深入浅出Hibernate>>作者的水平，他们确实都是比较牛的人物，也是我的偶像，像夏昕写的spring,hibernate等都是非常难得的好书。

 

所以，是不是我用的是hibernate3.0，而书本中用的是hibernate2.0等原因造成的？很迷茫。