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Re: soliciting your favorite (public) SPARQL queries!

From: Steve Harris <swh@ecs.soton.ac.uk>
Date: Thu, 21 Aug 2008 17:03:21 +0100
Cc: Lee Feigenbaum <lee@thefigtrees.net>, public-sparql-dev@w3.org, public-lod@w3.org
Message-Id: <25E2879B-8019-463C-9B6F-D69763E9CD89@ecs.soton.ac.uk>
To: Axel Polleres <axel.polleres@deri.org>

On 21 Aug 2008, at 16:51, Axel Polleres wrote:

>
> Tackling the question from the more theoretical side,
> I like non-monotonic SPARQL queries like the ones modeling set  
> difference.
>
> E.g.
> "Give me all persons *without* an email address" in a certain FOAF  
> graph.
>
>
> i) It is already folklore, that you can do that with using the ! 
> bound() filter outside an optional, i.e.
>
> SELECT ?X
> FROM G
> WHERE { ?X a foaf:Person
>        OPTIONAL { ?X foaf:mbox ?M}
>        FILTER (! bound(?X) ) }

Shouldn't that be !bound(?M) ?

- Steve
Received on Thursday, 21 August 2008 16:04:18 UTC

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