On 4/15/15 5:45 AM, Corey A Harper wrote:
> Hi Holger,
>
> I'm assuming by Dataset, you're talking about "a distinguished RDF
> graph and zero or more named graphs." [1]
>
> If I'm correct, I think the concern that both I and Tom raised
> remains. If I'm consuming data from an external source, and applying
> my own validation constraints, it seems overly restricting to say that
> these must be in the same Dataset. Or are you saying that, in my
> scenario, I would recast the consumed data, give it a new named graph
> ID, and consider it part of the same dataset for te purpose of my
> validation application?
In SPARQL implementations such as Jena, a dataset is primarily an
interface that maps names to graphs. A Graph is another interface that
can have any number of implementations. Many Graph implementations are
in fact wrappers of remote graphs. So there would not be any need to
copy data from a remote source into a local copy (although this may
speed things up).
And yes, datasets may also include new graph names for external graphs
or virtual graphs such as MultiUnion graphs (which we use a lot in
practice, e.g. to validate an imports closure graph).
And finally, there is the SPARQL SERVICE keyword, for specific SPARQL
end points.
Holger
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