Hi Lee !
Here are queries demonstrating the use of SPARQL CONSTRUCT for data
transformation between heterogeneous vocabularies. The following queries
allow to transform FOAF resources into vCard ones:
PREFIX vCard: http://www.w3.org/2001/vcard-rdf/3.0#
PREFIX foaf: http://xmlns.com/foaf/0.1/
CONSTRUCT { ?X vCard:FN ?name . }
WHERE { ?X foaf:name ?name . FILTER isLiteral(?name) }
CONSTRUCT {?X vCard:N _:a .
_:a vCard:Family ?fname .
_:a vCard:Given ?gname .}
WHERE { ?X foaf:firstName ?gname .
?X foaf:surname ?fname . }
CONSTRUCT { ?X vCard:URL ?url . }
WHERE { ?X foaf:workplaceHomepage ?url . FILTER isURI(?url) }
CONSTRUCT { ?X vCard:URL ?url . }
WHERE { ?X foaf:homepage ?url . FILTER isURI(?url) }
CONSTRUCT { ?X vCard:TITLE ?title }
WHERE { ?X foaf:title ?title . FILTER ( isLiteral(?T1) }
CONSTRUCT { ?X vCard:ORG _:a .
_:a vCard:Orgname ?name .
_:a vCard:URL ?url . }
WHERE { ?X foaf:currentProject ?Y
?Y foaf:name ?name .
?Y foaf:homepage ?url . }
CONSTRUCT { ?X vCard:ORG _:a .
_:a vCard:Orgname ?name . }
WHERE { ?X foaf:Group ?Y
?Y foaf:name ?name . }
One can remark this is only a partial transformation. That's because the
current SPARQL spec misses some features like aggregates and individual
generation. We would like for example to express the following CONSTRUCT
queries:
CONSTRUCT { ?X vCard:TEL _:a .
_:a rdf:value fn:substring(?T1,5) .
_:a a http://www.w3.org/2001/vcard-rdf/3.0#voice }
WHERE { ?X foaf:phone ?T1 .
FILTER ( isURI(?T1) )
Removing the "tel:" prefix of vCard:TEL, or
CONSTRUCT { ?X vCard:EMAIL _:a .
_:a rdf:value fn:concat("mailto:",?email) .
_:a a http://www.w3.org/2001/vcard-rdf/3.0#internet }
WHERE { ?X foaf:mbox ?email . }
adding the mailto: prefix to the vCard:EMAIL.
This is not possible in the current SPARQL spec. Our SPARQL++ [1]
extension tackle this. Maybe a future recommendation ? ;)
Cheers,
François
[1]http://www.scharffe.fr/pub/sparql++-for-mapping-between-rdf-vocabularies-ODBASE-2007.pdf
Lee Feigenbaum wrote:
Hi everyone,
I'm putting together a "SPARQL by Example" tutorial, which is, as the
name suggests, a step-by-step introduction to SPARQL taught almost
entirely through complete, runnable SPARQL queries.
So far, I've gathered a great deal of example queries myself, but I know
that many subscribers to these lists probably have favorite queries of
their own that you might be willing to share with me.
I'm looking for:
1) SPARQL queries
2) ...that can be run by anyone (no private data sets)
3a)...either by running the query against a public SPARQL endpoint
3b)...or by using a public SPARQL endpoint that will fetch
HTTP-accessible RDF data (e.g. sparql.org or demo.openlinksw.com)
4) ...that answers a real* question
5) ...and that is fun!**
* real is in the eye of the beholder, I imagine, but I'm not looking for
"finds the predicates that relate ex:s and ex:o in this sample RDF graph"
** fun is also in the eye of the beholder. fun can be a query on fun
data; a clever query that may illustrate a particular SPARQL construct
("trick"); a query that integrates interesting information; a query with
surprising results; etc.
thanks to anyone who is able to contribute!
Lee
PS I plan to make the tutorial slides available online under an
appropriate CC license once they are completed.
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email;internet:[EMAIL PROTECTED]
title:Phd Student/ Researcher/ Teaching Assistant
tel;work:0043 512 507 6448
tel;fax:0043 512 507 9872
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tel;cell:0043 650 72 31 408
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