JPA Hibernate: How to prevent join on retrieving?

Question

Suppose I have the following objects (one table per object) with this relations: A -> B -> C -> D

If I findById an instance of A, all B, C and D are returned which is not I want. Is this possible to force Hibernate only to return A (or only it's primitive properties)?

I know that I can write "SELECT a.x, a.y, a.z, ... FROM A" and then manually put the result list of objects in A, but this is somewhat timely as I should manually fill all properties. I have also checked all Hibernate query hints but nothing related.

Mohsen

Answer 1

If you have a constructor for A which fills all fields except the ones you don't want to join, you could select like this:

SELECT NEW A(a.x, a.y, a.z) FROM A a

Answer 2

You can specify fetch="select" and lazy="true" in your mapping. Especially if your relations -> are lists.

Answer 3

select a from A a ?

also, how have you've mapped your relations? lazy="proxy" and fetch="join"?