Re: Lee's feature proposal

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 UTC