hibernate 一对一关联关系 及其懒加载，总结

<hibernate-mapping package="cn.itcast.hibernate.domain">

    <class name="Person">
        <id name="id">
            <generator class="native" />
        </id>
        <property name="name" />
        <one-to-one name="idCard"/>
    </class>

</hibernate-mapping>

<hibernate-mapping package="cn.itcast.hibernate.domain">

    <class name="IdCard" table="id_card">
        <id name="id">
            <generator class="foreign">
                <param name="property">person</param>
            </generator>
            
        </id>
        <property name="name"/>
         
        <one-to-one name="person" constrained = "true"/>
    </class>

</hibernate-mapping>