RE: SPARQL queries property or class from a schema

I am not sure how expensive regex is compared to string comparison (for this
type of query) but here's one using regex:
Query and output saved at:   http://www.s3space.com/?p=308

PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT *
WHERE
{
?x ?p "Grand Prix"@en.
FILTER regex(str(?p), "^http://xmlns.com/foaf/0.1", "i")
}
limit 4

Regards,
Amit Joshi
http://www.s3space.com/ (Query the LOD)

-----Original Message-----
From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On
Behalf Of Mischa Tuffield
Sent: Friday, August 12, 2011 10:20 AM
To: Andy Seaborne
Cc: semantic-web@w3.org
Subject: Re: SPARQL queries property or class from a schema

Excuse the top-post.

You can brutal about it in SPARQL 1.0 and use filter regex. Something like :

.. FILTER ( regex( str(?p), "/http:\/\/xmlns\.com\/foaf/") )

It is kinda nasty, but will do the trick! 

Mischa 

Sent on the move

On Aug 12, 2011, at 5:55 PM, Andy Seaborne <andy.seaborne@epimorphics.com>
wrote:

> 
> 
> On 12/08/11 17:36, Jitao Yang wrote:
>> Dear all,
>> 
>> suppose we have DATA:
>> 
>> @prefix foaf: <http://xmlns.com/foaf/0.1/> .
>> 
>> _:a  foaf:name "Johnny Lee Outlaw" .
>> _:a  foaf:mbox <mailto:jlow@example.com <mailto:jlow@example.com>> .
>> _:b  foaf:name "Peter Goodguy" .
>> _:b  foaf:mbox <mailto:peter@example.org <mailto:peter@example.org>> .
>> _:c  foaf:mbox <mailto:carol@example.org <mailto:carol@example.org>> .
>> 
>> 
>> can we write a SPARQL query like:
>> 
>> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT *?property*
>> 
>> WHERE{
>>             ?x  foaf:*?property* "Peter Goodguy".
>> }
>> 
>> if we can not, can we write an equivalent SPARQL query? Namely, can 
>> we decompose schema and Class(or Property) in SPARQL query?
>> 
>> Thanks,
>> Jitao
> 
> SPARQL 1.1:
> 
> PREFIX foaf:   <http://xmlns.com/foaf/0.1/>
> SELECT ( substr( str(?p), strlen(str(foaf:))+1 )
>          AS ?property)
> 
> WHERE{
>    ?x ?p  "Peter Goodguy".
> }
> 
> 
> 
> In SPARQL 1.0, you can't return anything not already in the graph : in
SPARQL 1.1 you can do some manipulation of RDF terms.
> 
> Because SUBSTR is fn:substring, indexes are 1-based.
> 
>   Andy
>

Received on Monday, 15 August 2011 17:45:28 UTC