Hibernate中many-to-one unique="true" 和one-to-one

快来打我* 2021-06-24 13:59 300阅读 0赞

Hibernate one-to-one有两种形式：一是共享主键的形式进行关联，二就是独立外键的形式进行关联：  
例如：人（Person）和护照（Passwort）的关系是一对一的的关系：  
1）共享主键的形式：  
  
  
1）主表映射文件的写法：  
<class name="Person" table="t\_person">  
<id name="id" column="p\_id">  
<generator class="increment"> </generator>  
</id>  
<property name="name" column="p\_name" type="string"> </property>  
<property name="birthday" column="p\_birthday" type="date"> </property>  
<property name="email" column="email" type="string"> </property>  
<property name="phone" column="phone" type="string"> </property>  
<one-to-one name="passport" cascade="all"> </one-to-one>  
</class>  
  
  
2)辅表映射文件的写法：  
<class name="Passport" table="t\_passport">  
<id name="id" column="p\_id">  
<generator class="foreign">  
<param name="property">person </param> //person为Passport中的关系属性  
</generator>  
</id>  
<property name="serial" column="p\_serial" type="string"> </property>  
<property name="expiry" column="p\_expiry" type="integer"> </property>  
<property name="date" column="p\_date" type="date"> </property>  
<one-to-one name="person" constrained="true" cascade="all">  
</one-to-one>  
</class>  
  
  
   
  
  
  
  
2)独立外键的关联方式：  
  
  
1）主表映射文件的写法：  
<class name="Person" table="t\_person">  
<id name="id" column="p\_id">  
<generator class="increment"> </generator>  
</id>  
<property name="name" column="p\_name" type="string"> </property>  
<property name="birthday" column="p\_birthday" type="date"> </property>  
<property name="email" column="email" type="string"> </property>  
<property name="phone" column="phone" type="string"> </property>  
<one-to-one name="passport" property-ref="person" cascade="all"> </one-to-one> //person为实体类Passwort中的关系属性。  
</class>  
  
  
2)辅表映射文件的写法：  
<class name="Passport" table="t\_passport">  
<id name="id" column="p\_id">  
<generator class="increment">  
</generator>  
</id>  
<property name="serial" column="p\_serial" type="string"> </property>  
<property name="expiry" column="p\_expiry" type="integer"> </property>  
<property name="date" column="p\_date" type="date"> </property>  
<many-to-one unique="true" name="person" column="pss\_id">//pss\_id为外键列  
</one-to-one>  
</class>