单向一对一主键关联

public class Person {
      private int id;
      
      private String name;
      
      private IdCard idCard;

      public IdCard getIdCard() {
             return idCard;
      }

      public void setIdCard(IdCard idCard) {
             this. idCard = idCard;
      }

      public int getId() {
             return id;
      }

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

      public String getName() {
             return name;
      }

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

public class IdCard {
      private int id;
      
      private String name;

      public int getId() {
             return id;
      }

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

      public String getName() {
             return name;
      }

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

<hibernate-mapping>
      <class name ="com.bjpowernode.hibernate.IdCard" table= "t_idCard">
             <id name ="id">
                   <generator class ="native"/>
             </id >
             <property name ="cardNo"/>
      </class >
</hibernate-mapping>

<hibernate-mapping>
      <class name ="com.bjpowernode.hibernate.Person" table= "t_person">
             <id name ="id">
             <!-- 采用foreign生成策略，foreign会取得关联对象的标识 -->
                   <generator class ="foreign">
                   <!-- property指关联对象 -->
                         <param name ="property">idCard</ param>
                   </generator >
             </id >
             <property name ="name"/>
             <!-- one-to-one指示hibernate如何加载其关联对象，默认根据主键加载
                  也就是拿到关系字段值，根据对端的主键来加载关联对象
                  
                  constrained="true"标识当前主键还是一个外键
                  参照了对端的主键（IdCard的主键），也就是生成外键约束语句 -->
             <one-to-one name ="idCard" constrained="true"/>
      </class >
</hibernate-mapping>

双向一对一主键关联

<hibernate-mapping>
      <class name ="com.bjpowernode.hibernate.IdCard" table= "t_idCard">
             <id name ="id">
                   <generator class ="native"/>
             </id >
             <property name ="cardNo"/>
      
             <one-to-one name ="person" />
      </class >
</hibernate-mapping>

<hibernate-mapping>
      <class name ="com.bjpowernode.hibernate.Person" table= "t_person">
             <id name ="id">
                   <generator class ="native"/>
             </id >
             <property name ="name"/>
             <many-to-one name ="idCard" unique="true"/>
      </class >
</hibernate-mapping>

<hibernate-mapping>
      <class name ="com.bjpowernode.hibernate.IdCard" table= "t_idCard">
             <id name ="id">
                   <generator class ="native"/>
             </id >
             <property name ="cardNo"/>     
             <one-to-one name ="person" property-ref="idCard"/>
      </class >
</hibernate-mapping>