Superkey由三個屬性組成 - 如何應對Hibernate？

Question

考慮一個relation with a candidate key of three attributes：

alt text http://img576.imageshack.us/img576/9082/sampleu.png

我在想，如果有人可以給我一個Hibernate的配置文件的例子嗎？

Answer 1

... 
<class name="Topic" table="topics"> 
    ... 
    <set name="candidatures" table="Topic_has_Count_has_Date"> 
     <key column="TOPIC_ID"/> 
     <composite-element class="TopicCountDate"> 
      <parent name="topic"/> 
      <many-to-one name="count" class="Count" column="COUNT_ID"/> 
      <many-to-one name="date" class="Date" column="DATE_ID"/> 
     </composite-element> 
    </set> 
</class> 
<class name="Date" table="dates"> 
    ... 
    <set name="candidatures" table="Topic_has_Count_has_Date"> 
     <key column="DATE_ID"/> 
     <composite-element class="TopicCountDate"> 
      <parent name="date"/> 
      <many-to-one name="count" class="Count" column="COUNT_ID"/> 
      <many-to-one name="topic" class="Topic" column="TOPIC_ID"/> 
     </composite-element> 
    </set> 
</class> 
<class name="Count" table="counts"> 
    ... 
    <set name="candidatures" table="Topic_has_Count_has_Date"> 
     <key column="COUNT_ID"/> 
     <composite-element class="TopicCountDate"> 
      <parent name="count"/> 
      <many-to-one name="date" class="Date" column="DATE_ID"/> 
      <many-to-one name="topic" class="Topic" column="TOPIC_ID"/> 
     </composite-element> 
    </set> 
</class>