如何使用<join>标签加入hibernate映射文件中的两列？

Question

我需要将单个类映射到两个表(两个表都有多列主键).假设TABLE1具有id1,id2,id3,并且TABLE2具有id1,id2作为主键.现在编写映射文件时,我会执行以下操作:

<hibernate-mapping package="beans">
  <class name="TABLE1Class" table="TABLE1">
    <composite-id name="table1PK" class="TABLE1PKClass">
        <key-many-to-one name="id1" class="ID1Class" column="id1"/>
        <key-many-to-one name="id2" class="ID2Class" column="id2"/>
        <key-many-to-one name="id3" class="ID3Class" column="id3"/>
    </composite-id>
    <property name="someProperty" type="integer" not-null="true" column="x"/>
    <join table="TABLE2">
        <key column="id1" />
        <!-- <key column="id2"/> The join tag accepts only one key tag!!! 
How do I map the second key??? -->
        <property name="propertyFromTable2" type="float" not-null="true"/>
    </join>
  </class>
</hibernate-mapping>

如您所见,join标记只接受一个键标记!如何映射第二个ID？

亲切的问候,
暴君
PS:圣诞快乐,快乐和富有成效的新年;)

Answer 1

<key>可能包含多个<column>元素：

<key>
    <column name = "id1" />
    <column name = "id2" />
    <column name = "id3" />
</key>