<one-to-one>是否需要在PO中定义关联对象的引用？(foreign

对象A:B = 1:1

public class A {
    private Long id;  // A的主键
}

public class B {
    private Long id;  //外键
   [color=red]// private A aRef;[/color]
}

B.hbm.xml
<one-to-one name="id" class="A" constrained="true" cascade="save-update"/>

请问，一定需要红色的那行才能够实现<one-to-one>的关系吗？例如要求保存B的时候可以级联保存A。[/i]

补充B.hbm.xml

<id name="id" column="ID" type="long">
      <generator class="foreign">
           <param name="property">id</param>		
      </generator>
</id>
<one-to-one name="id" class="A" constrained="true" cascade="save-update"/>

B中需要定义A的引用吗？
private A aRef;
不然我发现在

A a = new A();;
a.setXXX();;
……
B b = new B();;
b.setXXX();;
b.setId(a.getId(););;
session.save(b);;

会跑异常，说No persister for:B

要。

可我把id换成A的引用，也不行：

net.sf.hibernate.MappingException: No persister for:

映射

<class name="com.ebao.test.hibernate.policy.CiPolicy" table="T_CI_POLICY" proxy="com.ebao.test.hibernate.policy.CiPolicy" dynamic-update="true" dynamic-insert="true">
		<id column="POLICY_ID" type="long">
			<generator class="foreign">
				<param name="property">policy</param>				
			</generator>
		</id>
		<one-to-one name="policy" class="com.ebao.test.hibernate.policy.Policy" constrained="true" cascade="save-update"/>
……

<class name="com.ebao.test.hibernate.policy.Policy" table="T_POLICY_GENERAL" proxy="com.ebao.test.hibernate.policy.Policy" dynamic-update="true" dynamic-insert="true">
		<id name="policyId" column="POLICY_ID" type="long">
			<generator class="sequence">
				<param name="sequence">S_POLICY_GENERAL__POLICY_ID</param>
			</generator>
		</id>
<!--这里没有定义到子对象的one-to-one-->
……

CiPolicy的代码：

private Policy policy;
public Policy getPolicy(); {
		return policy;
	}
public void setPolicy(Policy pol); {
		policy = pol;
	}

保存动作的代码：

Policy policy = new Policy();;			
policy.setXXX(new BigDecimal(1.0000););;			
						
			// second create one ci policy
			CiPolicy ciPolicy = new CiPolicy();;
			ciPolicy.setTradeCode(new Long(5););;
			ciPolicy.setPolicy(policy);;				sess.save(ciPolicy);;
			sess.flush();;

它的意思是你没有为一个类定义映射（或者你没有把它的映射加到Configuration中），和one-to-one又没有关系。

  第二次犯这个错误了，谢谢斑竹！