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Re: Requirement: queries written as RDF

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Fri, 2 Apr 2004 11:07:03 +0300
Message-Id: <B9B8A722-847C-11D8-B128-000A95EAFCEA@nokia.com>
Cc: Rob Shearer <Rob.Shearer@networkinference.com>, public-rdf-dawg@w3.org
To: "ext Eric Prud'hommeaux" <eric@w3.org>

On Apr 02, 2004, at 07:27, ext Eric Prud'hommeaux wrote:

> ... Once we know how to express a variable in the RDF model, I
> think the query expression will fall out.

I believe that RDFQ does this in a very intuitive and effective manner.

E.g. (using Turtle)

Match all resources where the dct:created value is equal to the
dct:modified value:

[a rdfq:Query;
       [a rdfq:Target;
          dct:created  [a rdfq:Value; rdfq:id "x"];
          dct:modified [a rdfq:Value; rdfq:id "x"]

or minimally (presuming domain/range closures and RDFQ default 

[:target [dct:created  [:id "x"]; dct:modified [:id "x"]]].

(results are a graph consisting of the descriptions of the matched 



Return the title and description for all resources with a dct:modified
value greater than one week ago (modified in the past week):

[:select ("title" "description");
  :target [dc:title       [:id "title"];
           dc:description [:id "description"];
           dct:modified   [:gt one-week-ago]]].

(results are a graph consisting of the variable bindings)



Patrick Stickler
Nokia, Finland
Received on Friday, 2 April 2004 03:12:24 UTC

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