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Hibernate version:
hibernate 3

I am trying to put in a special 'NULL' type for a property. By this, I mean that the database I am working with is a legacy system which uses '0' as meaning NULL.

I would like to find a generic solution to this so that I don't have to write custom types everytime that this happens, and that the createSchema does not create foreign keys for this columns, since obviously they are meaningless.

Is there a way of doing this?

No, not without UserTypes and also very difficult for associations.

If I were to add this functionality, could it incorporated into the main code base, or does it go against some philosophy?

I don't think that it would be necessary for assoiciations, since in general, even in a legacy db, the row would just not be there.

Three-valued logic is inappropriate for a data model (SQL shows that fairly well in its weirdness with NULLs) and a faked three-valued logic doesn't make it better. Nothing about philosophy, just data management basics.

True - I am not arguing that this is remotely a good thing, but given the prevalence of legacy databases, wouldn't it be useful?

I mean, composite-keys are idiotic as well, but one of the reasons that I choose Hibernate was because of its support for bizarre legacy models.

This can already be done with some effort - there is an old forum thread about it, search for it. Most likely this won't get any more supported.

ok - I found them. I looked yesterday, but obviously I wasn't typing in the right thing:

http://forum.hibernate.org/viewtopic.ph ... highlight=

http://forum.hibernate.org/viewtopic.ph ... key+legacy

Thanks for all the help.