java - 在复合键 hibernate xml 中映射复合键

Question

这就是我想要做的，将一个对象映射到另一个具有相同主键的表。下面是一个示例，基本上我有一个带有复合键的对象，该对象具有另一个表的复合键，但我不知道如何将两者都包括在内以创建正确的对象键。我突出显示了错误的行，它只包含键的一个属性。

  <class name="BusinessRuleObject" table="BUSINESS_RULE_OBJECTS" schema="DB">
    <composite-id name="businessRuleObjectId" class="BusinessRuleObjectId">
      <key-property name="sameIdCode" column="ID_CD" />
      **<key-many-to-one name="businessRule" class="BusinessRule" column="BUSINESS_RULE" />**
    </composite-id>
    <!-- ... STUFF GOES HERE -->
  </class>

  <class name="BusinessRule" table="BUSINESS_RULE_STRINGS" schema="DB">
    <composite-id name="businessRule2ID" class="BusinessRule2ID">
      <key-property name="sameIdCode" column="ID_CD" />
      <key-property name="businessRuleCode" column="BUSINESS_RULE" />
    </composite-id>
    <!-- TOTALLY DIFFERENT STUFF GOES HERE -->
   </class>

Answer 1

复合外键只有一个属性businessRule包括在内，因为 <key-many-to-one只声明一列 BUSINESS_RULE .它应该声明它引用的复合键的两列 BUSINESS_RULE和 ID_CD在你的例子中。通过添加 ID_CD列到 <key-many-to-one您需要删除或重命名 <key-property name="sameIdCode" column="ID_CD" /> 列的元素元素。

协会<key-many-to-one至 businessRule对象应该像这样映射:

<composite-id name="businessRuleObjectId" class="BusinessRuleObjectId"> 

  <key-many-to-one name="businessRule" class="BusinessRule" >
     <column name="ID_CD" />
     <column name="BUSINESS_RULE" />
  </key-many-to-one>

</composite-id> 

Hibernate reference documenation
5.1.7. composite-id
Components as composite identifiers