Re: DAGs and recursive queries

Thanks for your answers guys. I've got a cold right now and my brain
is mush, so I can't comment intelligently on your suggestions just
yet. I just wanted to express my thanks for your time.

Jeff, one book you might want to look at is Joe Celko's Trees and
Hierarchies in SQL for Smarties.

http://www.amazon.com/Hierarchies-Smarties-Kaufmann-Management-Systems/dp/1558609202

If the connectby() function is like the Oracle connectby function,
then perhaps it will suit my needs. The categorization scheme will
nearly always have multiple parents for all but the topmost node. Each
category stores serialized method calls for CRUD operations on objects
within the category, which are requested by the application for all
interactions with stored objects (though I'd like to be able to cache
them too, but that's in the application domain). Each object stored in
the database will belong to at least one category, but I expect they
will normally belong to many categories. When I create a new object of
categoryD, which is a child of categoryC and categoryB, which are
children of categoryA, then my application will need the CREATE method
calls from all parents, as well as the object category itself. I'd
like them all returned from one query, possibly ordered according to
the distance from the child node.

Oops, I'm trying to comment intelligently. Better stop now.

Cheers,
Paul