Question

Given the following entity definitions:

@Entity
class abstract A {
    Collection<A> parents;
}


@Entity
class B extends A {

}


@Entity
class C extends A {

}

is it possible to define a method which returns all entities of type B & C having a given parent, without having to make two separate calls and then merging the results?

Collection<A> getAllByParentId(long id)

Answer 1

It should be as simple as this:

List<A> results = entityManager
                      .createQuery("Select a from A a", A.class)
                      .getResultList();