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[protege-owl] online SPARQL query tool

babar shahzad babarathotmail at yahoo.com
Sun Mar 29 09:04:16 PDT 2009



thanX J; and sorry Tania & J.

> OK, my other question is about can you kindly tell me about some  
> framework that uses  SPARQL  as query language, have some good  
> documentation & examples too; preferably.

actually I wanted to ask same question as above for SQWRL, SPARQL is a mistake. 



 
Babar Shahzad Chaudary, 
+358408532112         
Deptt of Information Processing
Science,
University of Oulu, Finland.



----- Original Message ----
From: James Howison <james at howison.name>
To: User support for the Protege-OWL editor <protege-owl at lists.stanford.edu>
Sent: Sunday, March 29, 2009 6:35:10 PM
Subject: Re: [protege-owl] online SPARQL query tool


On 28 Mar 2009, at 5:35 PM, babar shahzad wrote:

>
>
> thanX a lot Tania for your such brief answer.
>
> OK, my other question is about can you kindly tell me about some  
> framework that uses  SPARQL  as query language, have some good  
> documentation & examples too; preferably.
>
>> However,
>> SPARQL will give you the asserted statements, and not the inferred  
>> ones
>> (at least the Protege implementation).
>
> But ' Semantic web for working ontologist ' by Jim Hendler et all  
> states .....
>
> shop: Henleys rdfs:subClassOf shop:Shirts .
> shop: ChamoisHenleys rdf:type shop:Henleys .
>
> Suppose we have a SPARQL triple pattern that we use to examine these  
> triples. Thus:
>
> ?x rdf:type shop:Shirts.
>
> type propagation rule: the following single result will be returned:
> ?x = shop:ChamoisHenleys

This is true if you are working with an ontology that has been  
'realized' by an OWL (or RDFS) reasoner.  I think of the reasoner  
sitting between the query and the asserted statements, so that when  
you query, you get answers based on the 'full set', asserted +  
inferred statements.

What Tania is saying is that the SPARQL tab in Protege works only  
against the asserted statements, the reasoner is not consulted, so  
results that rely on inferred statements are not returned.

As they say, you may have more luck with the SQWRL or DL-Query tabs,  
but you can also do this in SPARQL, but only stepping outside  
Protege.  For example using the Jena framework and an OntModel with an  
appropriate reasoner spec. Making SPARQL queries against that will  
produce the results you expect above.

I understand the difficulties of using SPARQL for some types of  
queries, particularly complex queries about the tbox (i.e. finding  
certain types of restrictions etc), I have no problems using SPARQL  
for simpler queries for statements about individuals (including their  
properties).  The key is to look at your data, preferably after  
reasoning, in Turtle format.

I'm not sure whether/how one programatically uses SQWRL or DL-query  
queries, but I believe it is possible.

I guess my point is that, for SPARQL at least, the issue of a reasoner  
is separate from the query language.  ie. SPARQL can be used with or  
without a reasoner, I think that SQWRL and DL-query always involve a  
reasoner.

--J 
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