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Re: unsaid/not: any champions?

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 04 Oct 2004 16:09:14 +0100
Message-ID: <4161679A.7070107@hp.com>
To: Dan Connolly <connolly@w3.org>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>

I also think it will have significant impact on the design and wouldn't
want this feature to defocus our efforts.  It seems to force either a
logical assertion view of the world or a procedural interpretation.  We
have some implementation experience to go on (log:notIncludes in cwm and
Euler) but are there any database-backed systems that provide something of
this kind?

Simon/Tom - does Kowari prvide any similar feature?  I have had requests
for it in the past but it is not a common request (I guess I have had less
than 5 such requests).

As it is an objective - "4.3 Non-existent Triples" - we have some room for
manoeuvre.

http://www.w3.org/2001/sw/DataAccess/UseCases#d4.3


I would note that limited cases can be with extension functions,
particularly testing for the absence of a single triple after variables
have been bound.  Optionals can be used as the basis for post-query
checking by the application in some cases.  The ASK form is also relevant.

For this publishing cycle, I am inclined to leave a placeholder in the doc
and possibly explicitly note that this feature may fall below the cut
line.  The sort of feedback I'd like to see is real use cases to gauge the
overall value.   If there is no feedback, then we drop it.

	Andy

Dan Connolly wrote:
> We still have an unsaid issue...
>   http://www.w3.org/2001/sw/DataAccess/issues#unsaid
> 
> but recent design drafts don't say much about it...
>   http://www.w3.org/2001/sw/DataAccess/rq23/#unsaid
> 
> and if we're going to do it, I think it'll have significant
> impact on the design; I'm disinclined to put the question
> on the SOURCE issue until I have a clear picture of where
> we're going with UNSAID.
> 
> I thought maybe we had adopted a requirement to do UNSAID,
> but I can't confirm from our requirements document.
>   http://www.w3.org/TR/rdf-dawg-uc/#req
> 
> If anyone would champion this feature, let him/her speak
> now... or soon (in the next few weeks)... or... wait
> until after we get a 1st version of SPARQL to REC.
> 
> It's also in order to propose that UNSAID should not
> be in SPARQL, or that it should be postponed until
> a later version.
> 
> 
Received on Monday, 4 October 2004 15:09:25 GMT

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