Re: SPARQL queries property or class from a schema

On Fri, Aug 12, 2011 at 18:55, 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
>
>
Dear Andy,

I think that this query:
-------------------------------------------------------------
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".
}
-------------------------------------------------------------

can not fix the shema foaf, because it just calculate the length of foaf,
therefore if we have foaf2:
<http://xmlns.com/foaf/0.2/<http://xmlns.com/foaf/0.1/>>,
with the same length as foaf, then, the data in foaf2 can also be queried
out.

Am I right?

If I am right, do we have the method to fix the shema or propery/class?

Thank you!

Best regards,
Jitao