Hibernate / JPA：是否可以在单个查询中检索异构实体？ [英] Hibernate/JPA: Is it possible to retrieve heterogeneous entities in a single query?

问题描述

我有2个实体：EntityA和EntityB。

它们是无关的，我不能将它们放在继承树中，以避开此问题范围之外的某些限制。

但是我需要在同一个JPQL或HQL查询中包含包含两个实体的所有实例的混合列表。这是可能的JPA甚至Hibernate直接？

我需要这样的事情：

  FROM EntityA WHERE fieldA = 1 
 UNION 
 FROM EntityB WHERE fieldB =aa
  

任何提示？

解决方案

嗯，我终于明白了。 b

它足以让实体实现一个通用接口（甚至不需要在Hibernate中声明该接口）。

然后，这样的查询可以完成：

  FROM my.package.CommonInterface obj 
 WHERE obj IN（FROM EntityA WHERE fieldA = 1）OR 
 obj IN（FROM EntityB WHERE fieldB ='a'）
  

这样，您检索 List< CommonInterface> 。

问题解决了。

I have 2 entities: EntityA and EntityB.

They are unrelated, and I cannot put them in a Inheritance tree for some restrictions out of the scope of this question.

But I need to get in the same JPQL or HQL query a mixed List containing all the instances of both entities. Is this possible with JPA or even Hibernate directly?

I need somethign like this:

FROM EntityA WHERE fieldA=1
UNION
FROM EntityB WHERE fieldB="aa"

Any hint?

解决方案

Well, I finally figured it out.

It is enought to make the entities implement a common interface (it is not even needed to declare this interface on Hibernate).

Then, a query like this can be done:

FROM my.package.CommonInterface obj
WHERE obj IN (FROM EntityA WHERE fieldA=1) OR
      obj IN (FROM EntityB WHERE fieldB='a')

This way, you retrieve a List<CommonInterface>.

Problem solved.

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