one to one(join column in right place) causes HQL eager fetch failure
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Brett Meyer July 8, 2014 at 3:10 PM
Bulk rejecting stale issues. If this is still a legitimate issue on ORM 4, feel free to comment and attach a test case. I'll address responses case-by-case. Thanks!
Brett Meyer April 7, 2014 at 5:41 PM
In an effort to clean up, in bulk, tickets that are most likely out of date, we're transitioning all ORM 3 tickets to an "Awaiting Test Case" state. Please see http://in.relation.to/Bloggers/HibernateORMJIRAPoliciesAndCleanUpTactics for more information.
If this is still a legitimate bug in ORM 4, please provide either a test case that reproduces it or enough detail (entities, mappings, snippets, etc.) to show that it still fails on 4. If nothing is received within 3 months or so, we'll be automatically closing them.
Thank you!
Dean Hiller February 18, 2010 at 7:23 PM
YES YES YES, I just found a workaround(thank god). Use ManyToOne and OneToMany and it now goes back to a single select!!!!
yeahhhhhhhh
See the end of this post...
The test case and all code can be found in here....(just modified the Cat->Kitten example till it broke)....
https://forum.hibernate.org/viewtopic.php?f=1&t=1002721&p=2425506#p2425506
basic summary though is if you have
SELECT s FROM Cat s inner join fetch s.kitten
and you redefine Cat->Kitten to be OneToOne, it works great if JoinColumn is on kitten, but if you move JoinColumn to Cat, it results in a 1+N select where the first sql got all the data needed by hibernate to fill in the Cats and their kitten. We have a 100 page result set that is doing 1+N selects here.
ie. if you leave the join column on kitten, the following sql is 1+N then....
SELECT k FROM Kitten k inner join fetch k.cat; (ie. a more likely case since there may be Cats without kitten, but a kitten always have a cat...that is the situation we have in our object model).
so onetoone eager fetch joins only work on half the cases out there from what I can tell and you get lucky if your join column is on the right object.