hibernate一对一关系 —- 主键同步

<?xml version="1.0" encoding="UTF-8"?>
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 <hibernate-mapping package="com.itheima.domain" >
 	<class name="Address" table="t_Address"   >
		<id name="id" column="id"    >
		
			<generator class="foreign">
			<!-- 作为外键时引用哪个属性 -->
				<param name="property">company</param>
			</generator>
		</id> 
			
		<property name="name" column="name" type="string" ></property>
		<!-- 配置一对一关系 -->
		<one-to-one name="company" class="Company" constrained="true"  ></one-to-one>
 	</class>
 </hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
 <hibernate-mapping package="com.itheima.domain" >
 	<class name="Company" table="t_Company"   >
		<id name="id" column="id"    >
			<generator class="native"></generator>
		</id> 
			
		<property name="name" column="name" type="string" ></property>
		<!-- 配置一对一
		one-to-one : 默认使用主键同步策略完成一对一的表关系体现.
		cascade:
		fetch:
		lazy:
		 -->
		<one-to-one name="address" class="Address"> </one-to-one>
 	</class>
 </hibernate-mapping>