Re: SPARQL results in RDF

Hi Hugh,

I recently stumbled over this post by the TopBraid/SPIN guys. Maybe
this is appropiate for your usecase.

http://composing-the-semantic-web.blogspot.ch/2013/06/spin-vocabulary-for-column-metadata.html

Regards,
Jerven
On Sun, Sep 22, 2013 at 1:29 AM, Hugh Glaser <hg@ecs.soton.ac.uk> wrote:
> Thanks Jerven, you may well be right!
> SELECT DISTINCT * WHERE
> { ?s foo:bar ?o }
> would do.
> And things like
> SELECT DISTINCT * WHERE
> { ?v1 foo:bar ?o . ?v1 ?p1 ?v2 . ?v2 ?p2 ?v3 }
> and then probably get back an identifier for each result, so that I can find out what are the values of the ?p* and ?v*
> I think essentially the sort of thing that dbpedia/virtuoso is giving me.
> (By the way, Kingsley, replying to this has caused me to notice that the rdfxml does not rapper very nicely - sorry to report!
> rapper: Error - URI file:///home/hg/sparql.rdf:8 - property element 'solution' has multiple object node elements, skipping.)
>
> Best
> Hugh
>
> On 21 Sep 2013, at 23:32, Jerven Bolleman <jerven.bolleman@isb-sib.ch>
>  wrote:
>
>> Hi Hugh,
>>
>> I think you disregarded the CONSTRUCT queries a bit to quickly. This is what you use when you want to get back triples.
>> If you want back result columns you use SELECT. If you want describe to the concept of result columns in RDF then you are
>> on your own.
>>
>> Maybe if you explain what you want to represent then we can have a bit more of an informed discussion.
>>
>> Regards,
>> Jerven
>> On Sep 21, 2013, at 8:38 PM, Hugh Glaser <hg@ecs.soton.ac.uk> wrote:
>>
>>> Many thanks, William, and for confirming so quickly.
>>> (And especially thanks for not telling me that CONSTRUCT does what I want!)
>>> I had suddenly got excited that RDF might actually be useable to represent something I wanted to represent, just like we tell other people :-)
>>> So it is all non-standard, as I suspected.
>>> Ah well, I'll go back to trying to work with XML stuff, instead of using my usual RDF tools :-(
>>> Very best
>>> Hugh
>>>
>>> On 21 Sep 2013, at 19:14, William Waites <ww@styx.org>
>>> wrote:
>>>
>>>> Hi Hugh,
>>>>
>>>> You can get results in RDF if you use CONSTRUCT -- which is basically
>>>> a special case of SELECT that returns 3-tuples and uses set semantics
>>>> (does not allow duplicates), but I imagine that you are aware of this.
>>>>
>>>> Returning RDF for SELECT where the result set consists in n-tuples
>>>> where n != 3 is difficult because there is no direct way to represent
>>>> it.
>>>>
>>>> Also problematic is that there *is* a concept of order in SPARQL query
>>>> results while there is not with RDF.
>>>>
>>>> Also the use of bag semantics allowing duplicates which also does not
>>>> really work with RDF.
>>>>
>>>> These, again, could be kludged with reification, but that is not very
>>>> elegant.
>>>>
>>>> So most SELECT results are not directly representable in RDF.
>>>>
>>>> Cheers,
>>>> -w
>>>>
>>>
>>>
>>
>> -------------------------------------------------------------------
>> Jerven Bolleman                        Jerven.Bolleman@isb-sib.ch
>> SIB Swiss Institute of Bioinformatics      Tel: +41 (0)22 379 58 85
>> CMU, rue Michel Servet 1               Fax: +41 (0)22 379 58 58
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>>
>
>



-- 
Jerven Bolleman
me@jerven.eu

Received on Thursday, 10 October 2013 08:09:51 UTC