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Re: Proposal to drop disjunction requirement

From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Date: Sat, 2 Oct 2004 10:56:45 +0100
To: DAWG public list <public-rdf-dawg@w3.org>
Message-ID: <20041002095645.GE28819@login.ecs.soton.ac.uk>

On Fri, Oct 01, 2004 at 04:15:11PM -0500, Dan Connolly wrote:
> On Fri, 2004-10-01 at 13:21, Steve Harris wrote:
> > On Fri, Oct 01, 2004 at 01:22:24 -0400, Kendall Clark wrote:
> > > 
> > > On Fri, Oct 01, 2004 at 06:17:16PM +0100, Steve Harris wrote:
> > > 
> > > > conjunctive ones, but it explodes the number of queries needed
> > > > dramatically.
> > > 
> > > In cases where the implementation strategy is based on RDBMS/SQL or in
> > > every case? I genuinely don't know.
> > 
> > In every case - the algorithm prduces a number of prurely conjunctive
> > expressions from a mixed dis/con-juntive one.
> 
> Really? I can't think of an algorithm for the simplest case:
> 
>  (<book1> dc:title "War and Peace") OR (<book2> tc:title "Moby Dick")
> 
> Oh.. you mean you turn it into *multiple* queries. Maybe I see.

Yes.
 
> Don't you need negation in some cases?

Um, possibly yes, that would be a problem for me if so, but not
neccesarily for all approaches.

> > Bear in mind that those are the /exact/ translations, the optional
> > expression users really write are the natural ones and dont have the hairy
> > disjuntive value constraints.
> 
> That seems to be the most relevant point/question, to me: do we
> expect users to find the optional constructs straightforward for 80%
> to 95% of the cases? Or do we expect them to say "hey; where's the OR
> thingy?" in their first week of usage?

I've never been asked for OR, but I have only a hundred or so end users,
Andy has far more than that and I think he mentioned he had seen requests
for OR, but not how many.

- Steve
Received on Saturday, 2 October 2004 09:56:51 GMT

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