- From: Harry Halpin <hhalpin@ibiblio.org>
- Date: Fri, 27 Jul 2007 18:38:11 -0400
- To: Bijan Parsia <bparsia@cs.man.ac.uk>
- Cc: Bruce D'Arcus <bdarcus@gmail.com>, bnowack@appmosphere.com, Garret Wilson <garret@globalmentor.com>, Semantic Web <semantic-web@w3.org>
Is it indeed difficult or impossible to write a SPARQL query over
rdf:List, particulary with the use of owl:sameAs as in:
<vCard:additionalNames rdf:parseType="Collection">
<rdf:Description owl:sameAs="Edward"/>
<rdf:Description owl:sameAs="Reeves"/>
</vCard:additionalNames>.
Can someone tell me precisely why and if so, does rdf:Seq help?
Currently consensus is heavily drifting towards rdf:List, but querying
in SPARQL is important.
-harry
Bijan Parsia wrote:
> On Jul 26, 2007, at 2:39 PM, Harry Halpin wrote:
>
>> Bruce D'Arcus wrote:
> [sni[]
>>> I'm now totally lost.
>>>
>>> Everyone I have talked to has discouraged use of rdf:Seq. AFAIK, you
>>> cannot really query it reliably with SPARQL either, though am not sure
>>> of that.
>> Is that true?
> [snip]
>
> Which? That everyone bruce has talked to discourages use of rdf:Seq? I
> don't know. I certainly do so discourage. But I discourage use of
> rdf:List too :)
>
> I don't know about "reliably". Someone later in the thread gave a
> pretty good query for getting at the values of containers. Ordering
> generally is done by term sorting, so _1 _2, etc. should work fine.
>
> There are implementation specific extensions (both actual and
> possible) e.g.
> http://thefigtrees.net/lee/sw/sparql-faq#transitiv8
>
> Back in the day, some engines had trouble with large numbers of
> properties, so the coined properties in a seq could cause trouble if
> one had no special ordering of them (e.g., if you naively mapped
> properties to tables, that could suck). But that strikes me as
> implementor lameness, which is also to be discouraged. :)
>
> Cheers,
> Bijan.
>
>
--
-harry
Harry Halpin, University of Edinburgh
http://www.ibiblio.org/hhalpin 6B522426
Received on Friday, 27 July 2007 22:38:40 UTC