Hibernate:一对一双向外键关联

一 环境：W7+Eclipse3.6+JDK1.6+MySQL
二 所用Hibernate版本：hibernate-distribution-3.6.0.Final
三 具体代码
1 Annotations版本

主导对象

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;

@Entity
public class A {
	private int id;
	private String name;
	private B b;

	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	
	public String getName() {
		return name;
	}

	@OneToOne
	@JoinColumn(name="bid")
        //指定关联列名
	public B getB() {
		return b;
	}
	public void setId(int id) {
		this.id = id;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setB(B b) {
		this.b = b;
	}
	
}

被参考对象

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;

@Entity
public class B{
	private int id;
	private String name;

	private A a;
        //参考了A对象中的属性B的名字：b,只要是双向关联mappedBy必设
       @OneToOne(mappedBy="b")
        public A getA() {   
           return a;   
        }   
   
        public void setA(A a) {   
          this.a = a;   
        }   
         
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	
	public String getName() {
		return name;
	}

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

XML版本

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping >
	 <class name="org.hibernate.model.A">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name"/>
	    <many-to-one name="b" column="bid"  unique="true"/>
    </class>
</hibernate-mapping>

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping >
	 <class name="org.hibernate.model.B">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name"/>
       <one-to-one name="a" property-ref="b"></one-to-one>
    </class>
</hibernate-mapping>

SQL

create table A (   
        id integer not null auto_increment,   
        name varchar(255),   
        bId integer unique,   
        primary key (id)   
)   
  
create table B (   
        id integer not null auto_increment,   
        name varchar(255),   
        primary key (id)   
)   
  
alter table A    
        add index FK418DB36D94 (bId),    
        add constraint FK418DB36D94    
        foreign key (bId)    
        references B (id)