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.

I have 2 entities: EntityA and EntityB.

它们是不相关的，我不能将它们放在继承树中，因为有些限制超出了这个问题的范围.

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

但是我需要在同一个 JPQL 或 HQL 查询中查询一个包含两个实体的所有实例的混合列表.这可以通过 JPA 甚至 Hibernate 直接实现吗?

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?

我需要这样的东西:

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

有什么提示吗?

推荐答案

好吧，我终于想通了.

让实体实现一个通用接口就足够了(甚至不需要在Hibernate上声明这个接口).

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

然后，可以进行这样的查询:

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')

通过这种方式，您可以检索List.

This way, you retrieve a List<CommonInterface>.

问题解决了.

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