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Re: Lee's feature proposal

From: Paul Gearon <gearon@ieee.org>
Date: Fri, 1 May 2009 11:07:07 -0500
Message-ID: <a25ac1f0905010907u3644ab4ar801e9ab80df16752@mail.gmail.com>
To: SPARQL Working Group <public-rdf-dawg@w3.org>
On Fri, May 1, 2009 at 10:35 AM, Kendall Clark <kendall@clarkparsia.com> wrote:
>
> On Fri, May 1, 2009 at 10:30 AM, Lee Feigenbaum <lee@thefigtrees.net> wrote:

<snip/>
> Again, fair enough, but we're roughly treating all the features as
> equivalently substantive in terms of how much it will take to get them
> specified, and I don't believe that's really true (nor does anyone
> else, I should think). Also, negation just strikes me as something we
> *have* to fix or we'll be embarrassed.

+1

This was the very first question I answered about how to use SPARQL,
and it has persisted as the most common question I see. Also, having a
syntactic construct for negation makes it easier for optimizers to
identify a subtraction operation, instead of the more general (and
slightly slower) filtered join. (Not that it eliminates the role of an
optimizer here, but it's still a win)

Regards,
Paul Gearon
Received on Friday, 1 May 2009 16:07:44 GMT

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