i'd like to accomplish something like the HQL:

from Cat cat
inner join cat.kittens as kittens0
inner join cat.kittens as kittens1
where kittens0.name = 'Fred'
and kittens1.name = 'Amy'

which would find cats that have at least two kittens, one named fred and another amy.

is this possible with the current criteria api? i've tried:

Criteria.createCriteria (Cat.class)
.createAlias ("kittens", "kittens0").add (Expression.eq ("name", "Fred"))
.createAlias ("kittens", "kittens1").add (Expression.eq ("name", "Amy"));

and judging from the debugging sql output, the criteria query overwrites the first association with the second, and i get only one inner join:

from Cat cat
inner join cat.kittens as kittens1
where kittens0.name = 'Fred'
and kittens1.name = 'Amy'

which of course fails at the database level for having no kittens0.

I have the same problem.

You might want to check out Expression.conjunction(). It implements AND clauses...Expression.disjunction() does ORs. I hope this helps. Here is a link to a post referencing a simmilar situation:

http://forum.hibernate.org/viewtopic.php?p=2186938

yes, this is a limitation, you can't join the same association twice.

Hi Gavin,

do you have some idea when this limitation can be removed, if possible?

Thanks in advance.

Ah .. not in a real hurry, it is due to how OuterJoinLoader works. (Historically, the Criteria query API was hacked in on top of the code that was originally used just for outer join fetching, so there are some slightly wierd limitations that don't affect HQL.)

What I'm seeing is that Hibernate 3.1 will probably concentrate on enhancements to Criteria query API (and perhaps also to HQL), it is not our priority for Hibernate 3.0.

Do you think in 3.1 that the Criteria API will be able to do everything that is possible in HQL? When I first chose Hibernate for a project over a year ago, it was instead of OJB, which I had already used. However, the shortcomings of the Criteria API quickly restricted it usage, which I lament. It is much easier to build queries with optional filters using the Criteria API than by trying to do a bunch of string concatenation. I think it is also easier to maintain and change queries, and to visually check for correctness.

Hi gavin!

I'm a bit sad that this known problem not seems to be knocked out in Hibernate 3.1 beta 3.
Especially, because i want to switch from OJB to Hibernate due to confusing, not really working OJB Aliases in complex Queries with long attribute paths over several foreign and inverse foreign keys.

I would really like to construct queries with Criteria in Hibernate, because of it's clear and consistent handling.

Do you know, if someone's working on this issue and if it will be implemented in the release 3.1?
If not, maybe i'll dig through the sources for fixing.

Thanx!

I'm in the same situation you are in terms of wanting to construct Criteria queries programmatically, and I'm currently running up against this same issue (the 'duplicate association'). I'm trying to build a Criteria query programmatically based on a set of criteria values passed into a function. The function must look through these values and add the criteria as needed. The entity I am querying for contains other entities as properties, some of which contain entities themselves, etc.

This seems like a pretty severe limit on the functionality of Criteria queries. Am I correct in assuming that what has been said above means you can not do something like this? :



...I do realize that you can accomplish the same thing by doing the following:



...however, if you are building a set of Criteria programmatically it is much more complicated to determine when it would be necessary to do this, especially when you are dealing with a large number of Criteria that may or may not affect a particular property (in this case, an object with multiple properties) within an entity.

I noticed a new JIRA was created a few weeks ago:

http://opensource2.atlassian.com/projects/hibernate/browse/HHH-1048?page=all

...is this a fix for this particular issue?

IMO, once this issue and the lack of the ability for Criteria queries to use the second-level object cache (i.e., the lack of functionality equivilant to Query's iterate() ) are resolved, the Criteria API will officially be rocking! =)

...ok, I read that incorrectly, it definitely is not about the issue I was referring to. =/

Correction, here is the JIRA for this issue:

http://opensource2.atlassian.com/projec ... se/HHH-879

This issue has been a thorn in my side on a project of mine since last summer, and has recently reared its head again to create an even bigger problem.

I CANNOT use HQL because of differences in performace between Criteria and HQL... specifically HQL ignores the maxFetchDepth paramenter, and created unsatisfactory performance for some of the operations we are attempting. Therefore I am reliant on Criteria.

I even spent some time going deep into the Hibernate code myself to try to fix the problem, but to no avail.

Can someone please tell me there is a plan to fix this?

As far as I can see, there was no progress on that. Is anything planned?

Hello Hibernate team,

Was this problem ever addressed and/or fixed?

Is it now possible to create a second join on the same association?

Need it urgently.. Is there a work around?

Regards,

Dmitry.

Any updates on this issue?

It seems it is still reproducible on Hibernate 3.1.3.