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Re: Data models as constraints

From: Hassan At-Kaci <hak@ilog.com>
Date: Tue, 16 Jan 2007 18:29:53 +0100
Message-ID: <45AD0B91.5040505@ilog.com>
To: Gerd Wagner <wagnerg@tu-cottbus.de>
CC: W3C RIF WG <public-rif-wg@w3.org>

Gerd Wagner wrote:

>>Thanks for your comment on my paper: you must be the fastest reader
>>that I have come across in my life! ;-)
> In fact, I'm not a fast reader at all, of course, I just managed to
> browse through your paper.

Now I understand better! :-)

>>Re. your comment, I must say thay I do not quite understand what it
>>has to do with either the topic of the article, nor  what it means.
>>What I wrote about is simple: because CLP makes rules and constraints
>>orthogonal, it offers a way to use rules over arbitrary data models
>>- not just data and FOTs. I then focused on the OSF and DL formalisms
>>seen as constraint systems for objects and inheritance. The nature of
>>the rules is *not* important and may be of all kinds including Horn,
>>(with or without negations or all kinds), Production, YouNameIt, ...
> OK, but you don't discuss that in your paper, do you?

Quoting from the paper (Section 3.3.2)

"Clearly, non-logical rules systems such as those based on
  condition/action production rules typically used in experts systems
  using object pattern-matching can also be expressed using OSF term
  entailment (as opposed to unification).

>>>How can you capture SQL, Prolog and production rules
>>>without supporting NaF?
>>Again the focus of my paper is *NOT* on the rules but (as the title
>>states it clearly) about *data models as constraint systems*.
>>Also, the nature of the paper is that of a (semi-formal) tutorial
>>- not an exhaustive survey about all known or possible ways to
>>conjugate rules and data. Perhaps you should write such an article?
> Come on, you are the expert here, not me!

You are as much as "expert" as I am I am afraid. My point though is
that you seem to have a precise idea of what you want and you are the
most competent to explain it.

> ...
>>At any rate, I am sorry that you find my work of debatable interest
>>for your needs, and I apologize for disappointing your expectations.
> Your paper is clearly of high value as a publication, but for my
> purposes I'd prefer to see a more RIF-focused version of it. 

Your personal purposes notwithstanding, one of the 2 reasons I wrote this
paper and have shared it with the RIF/WG is that I was explicitly asked
(by Jeff Pan, Alex Kozlenkov, and others at the last RIF F2F) to write
such a document explaining in more formal details my claims that data
models are constraint systems. The reason they requested it is because
they could not see clearly how of CLP scheme proposal for the RIF that
I have advocated without being sure how their own systems' data models
could be seen as constraints. I accepted the challenge, agreeing that
the onus was on me as the proposal's author to do so - hence the paper.
The feeling shared by most RIfers (I believe) is that (1) it was not so
obvious and (2) it was a topic of importance for the RIF. So it may be
not "RIF"-focused, but I think that it is definitely "RIF-relevant".

> -Gerd

Hassan At-Kaci
ILOG, Inc. - Product Division R&D
tel/fax: +1 (604) 930-5603 - email: hak @ ilog . com
Received on Tuesday, 16 January 2007 17:30:42 GMT

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