Hello Rajeev,
This support is technically possible but we should consider some issues
first.
1. Virtuoso uses quad store, not triple store so DESCRIBE implementation
should find graphs that contain data about subject before producing
actual result. For the sake of performance it will not even try to find
absolutely all graphs that may be useful. If one graph contains
Statements whereas other contains plain triples, should we stop search
for graphs if only one of them is found? If we should stop, which graph
should take priority?
2. It should be possible to configure whether rdf:Statements are
expected in the database. This is important because some applications
prefers to get DESCRIBE result that is a strict subset of the database
in order to add only statements that are not stored already or to make a
'diff' between data that are really stored in different sources.
3. Are rdf:Statements always stored in native-form quads or they may
come from RDF Views?
4. May native-form quads contain rdf:Statements about subjects generated
by RDF Views?
5. Do all four triples of { ?ST a rdf:Statement ; rdf:subject ?s
rdf:predicate ?p ; rdf:object ?o } always come from same graph or they
can come from up to four separate graphs?
6. If there are only three triples, { ?ST rdf:subject ?s
rdf:predicate ?p ; rdf:object ?o } but not { ?ST a rdf:Statement },
the DESCRIBE routine "MUST"/ "MUST NOT" / "MAY" return { ?s ?p ?o } in
the result set. Please suggest appropriate verb, 'RFC style'.
Best Regards,
Ivan Mikhailov,
OpenLink Software.
On Sun, 2008-01-06 at 03:21 +0530, Rajeev J Sebastian wrote:
> Hello Virtuoso Developers,
>
> Would it be possible for Virtuoso to support asserting triples which
> are indicated by a Statement ?
>
> I.e., consider the following fragment:
>
> :foo rdf:label "Foo".
>
> :spam a rdf:Statement; rdf:subject :foo; rdf:predicate dc:title;
> rdf:object "The Foo".
>
>
> and sparql similiar to:
>
> describe <myns:foo>
>
> Shouldn't it give the result similiar to:
>
> :foo rdf:label "Foo"; dc:title "The Foo".
>
>
> Regards
> Rajeev J Sebastian
