java - Hibernate/JPA: Is it possible to retrieve heterogeneous entities in a single query?

Question

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?

Answer 1

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.