Hibernate 主键关联中的一对一关联

基于外键关联的双向一对一关联也很常见。

<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<many-to-one name="address"
column="addressId"
unique="true"
not-null="true"/>
</class>
<class name="Address">
<id name="id" column="addressId">
<generator class="native"/>
</id>
<one-to-one name="person"
property-ref="address"/>
</class>

create table Person ( personId bigint not null primary key, addressId bigint not null unique )
create table Address ( addressId bigint not null primary key )

基于主键关联的一对一关联需要使用特定的id生成器。

<class name="Person">
<id name="id" column="personId">
<generator class="native"/>
</id>
<one-to-one name="address"/>
</class>
<class name="Address">
<id name="id" column="personId">
<generator class="foreign">
<param name="property">person</param>
</generator>
</id>
<one-to-one name="person"
constrained="true"/>
</class>