Hi all,
I found an inconsistency and I'd like to know if it's a known bug and if there's a workaround.
I'm using Hibernate 3.6.10.

This is my entity hierarchy:

Profile <= the base entity; it has a "ProfileType" column as a discriminator
Artist <= abstract, extends Profile
SoloArtist <= extends Artist, ProfileType='SA'
BandArtist <= extends Artist, ProfileType='BA'

If I make an HQL query like this:

this gets correctly translated to:

It even works for more complex cases like:

or when I have to put conditions on associated tables, like:

In all of these cases, the "where artist.ProfileType in ('SA', 'BA')" is always correctly generated. So far so good, it was not a so obvious use case!

However, when the abstract entity is put on the right side of a join, Hibernate does not complain, but generates an incomplete SQL. For instance, suppose an artist can write posts:

(please note: the real case is more complex, so the use of the "right join" might sound strange here, but it's just to show my problem; also, don't ask yourself why here I use artist.active and not user, active, it's not important)

What I get in this case is an SQL string like the following:

That is, in this case Hibernate does not produce the "where artist.ProfileType in ('SA', 'BA')" that is needed to discriminate between a generic Profile and an Artist.

Is there a reason? A workaround?

Thanks in advance.
Mauro.

As a workaround I tried to use the discriminator "class" property:



Hibernate does not complain, but generates the following:



which sounds like a supported use case, but handled in the wrong way.
To get the result I want, I have to write:



In this case, the correct where clause is generated: "(profile0_.ProfileType='SA' or profile0_.ProfileType='BA')".
However, this is not the ideal solution, since I must know in advance all the possible concrete implementations of Artist.

I understood why Hibernate behaves in this way... and it is reasonable. In fact, Post.owner refers generically to a Profile, not to an Artist. The fact I use the alias "artist" to refer to Post.owner isn't actually telling Hibernate it should join the post with an Artist, but just with a Profile called "artist".

So, the question is: is there a way to force Hibernate to join with an Artist, without having to explicitly select any possible concrete artist type using the "class" property?

I would have gladly used the left join instead of the right join, also because it sounds more "natural" to me; something like:



but how could I do that? The foreign key is Post.owner => Profile, I don't have the backward reference, so I don't know how to express it in HQL (if ever possible...).