Re: Canonical DB

From: Dmitry A. Kazakov <>
Date: Fri, 23 Jun 2006 12:42:53 +0200
Message-ID: <dc5jib8wsvx5.vh1ugt1litwe$>

On Fri, 23 Jun 2006 11:55:36 +0200, mAsterdam wrote:

> Googling for 'graphs RM' gives
> ;-), substituting 'relational' for 'RM' made me stumble on

I'm not sure that the latter is really "relational" in the sense of RM. The algebra of the relations between matched instances of pattern atoms is not necessary RA. [That's all I can derive from the text, I might be wrong.] The approach itself is common for text pattern matching, as well.

> If you don't mind getting your hands dirty:
> mentions
> some Oracle specifics, in
> Vadim Tropashko discusses two ways "to model a tree
> in the database". His new book might be on the way
> to the stores by now, but I did not find a reference.
> Joe Celko wrote

Reading such things one should always ask himself: what was lost? Any tree built in any way is a tree. Once you have it, it will not fully obey RA or whatever framework you used. That precisely means: an otherwise legal operation applied to a tree may kill it. It is so with all complex structures. Integers can be constructed as sets. But if you tried to arbitrarily apply set-theoretic operations to the sets representing individual integer numbers, you might get rubbish.

Dmitry A. Kazakov
Received on Fri Jun 23 2006 - 12:42:53 CEST

Original text of this message