Re: Union or not union for the default graph...

My problem with this is that it becomes a closed possibility provided by the store, and not the choice of the dataset provider. I mean: the SPARQL service description tells me about the default dataset at the SPARQL endpoint. Is there a way to tell the SPARQL engine to use or not to use the union of the graphs that are in a specific SPARQL query>

What am looking for is a way to tell the system: this is what I want. Do I want a quoting or a union semantics for my particular dataset? 

Ivan


On Apr 12, 2012, at 22:45 , Andy Seaborne wrote:

> 
> 
> On 12/04/12 21:31, David Wood wrote:
>> Hi all,
>> 
>> Perhaps we should provide a standard way for an RDF system to
>> advertise how the default graph. That would be sufficient to plug the
>> hole Ivan sees without forking the semantics, wouldn't it?
>> 
>> Linked Data systems already advertise a lot via VoID. This wouldn't
>> require much of an extension and needn't even be normative.
> 
> Description (using some kind of meta data language) is much better than
> putting in the core architecture.
> 
> And the amount of work needed is nice as well:
> 
> http://www.w3.org/TR/sparql11-service-description/#sd-uniondefaultgraph
> 
> (A TriG syntax shortcut would be nice as well, but not necessary if compatibility with current de facto syntax is deemed more important)
> 
> 	Andy
> 
> 


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Ivan Herman, W3C Semantic Web Activity Lead
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