Re: Queries over multiple graphs

On Tue, Sep 28, 2004 at 09:40:35AM -0500, Pat Hayes wrote:
> >On Tue, Sep 28, 2004 at 11:47:05AM +0100, Steve Harris wrote:
> >>
> >> In recent discussions over email and on IRC this morning we hit a
> >> difference of implementation in some RDF storage systems.
> >>
> >> In my system if you load multiple graphs with distinct source information
> >> and the same statement appears in 2 graphs there are two distinct
> >> statements. The same goes for statements that may be inferred by multiple
> >> routes.
> >
> >Discussing this further it appears to be a philosophical difference: does
> >an RDF store hold a single (merged) RDF graph with statements from
> >different sources, or does it hold a set of RDF graphs.
> 
> Surely the right answer is, yes. That is, it could be either. Its up 
> to the owner responsible for maintaining the store to decide. So the 
> QL ought to be able to handle both cases, which I think is the case 
> right now.

I agree, if so we have to agree on wether results are implicitly DISTINT
or if (A, A) == (A) in query results.

- Steve