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flexible SPARQL reification construct instead of hard-wired SOURCE keyword

From: Benjamin Nowack <bnowack@appmosphere.com>
Date: Fri, 14 Jan 2005 19:39:16 +0100
To: public-rdf-dawg-comments@w3.org
Message-ID: <PM-EH.20050114193916.A69B4.1.1D@192.168.27.2>


hi again,

an adjusted version of my comment from yesterday[1] as
just some extended food for thought. The idea is to
introduce a reification shortcut that could be used for
the SOURCE use cases and also for any other custom rdf
store extension:

[[[
...
SELECT ?s  ?p  ?o
WHERE ( ?s rdf:type foaf:Person )
      ( ?s ex:ppd ?ppd )
      ( ?ppd rdf:type foaf:PersonalProfileDocument )
      ( ?ppd foaf:primaryTopic ?s )
REIF  (?s ex:ppd ?ppd) sparql:source <http://trustMe.com/ppdDump>
      (?s ?p ?o) sparql:source ?ppd
      (?s ?p ?o) ex:addedDate "2004-01-13"
]]]

The reification constraint pattern 
 ([s] [p] [o]) [prop] [value]
would mean that there had to be an rdf:Statement with [s],[p],[o]
as rdf:subject,rdf:predicate,rdf:object, and that there's also
a matching ([statement] [prop] [value]) triple. store developers
could freely decide how to implement this extended functionality
(explicit reification or with quads etc.) but the query syntax
could be generic. and using URIrefs for the [prop]s instead of
a single built-in SOURCE keyword for n-tuple stores would
keep SPARQL extensible. 


regards and apologies for the (probably too) late comments,
benjamin

[1]
http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Jan/0002.html

--
Benjamin Nowack

appmosphere web applications
Kruppstr. 100
45145 Essen, Germany

http://www.appmosphere.com/
Received on Friday, 14 January 2005 18:39:56 GMT

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