- From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Date: Thu, 2 Jun 2005 09:44:39 +0100
- To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
On Thu, Jun 02, 2005 at 01:48:58AM -0400, Eric Prud'hommeaux wrote:
> Recording Yoshio and my whiteboard discussion here:
>
> Given this data:
> <c>:
> <A> knows <B>
>
> <d>:
> <B> mbox <mailto:b>
>
> It seems the following 4 expressions are all equivilent:
>
> (1) (Named Graphs (arbitrary pre-existing data)):
> FROM <c> <d>
> WHERE {
> GRAPH ?g { ?who knows ?whom } .
> GRAPH ?g { ?whom mbox ?mbox } .
> FILTER ?g = <c> || ?g = <d>
>
> (2) (Source (arbitrary pre-existing data)):
> FROM <c> <d>
> WHERE {
> SOURCE ?g { ?who knows ?whom } .
> SOURCE ?g { ?whom mbox ?mbox } .
> FILTER ?g = <c> || ?g = <d>
>
> (3) (No Default Graph):
> FROM <c> <d>
> WHERE {
> ?who knows ?whom .
> ?whom mbox ?mbox } }
>
> (?) (Source + CLEAR (arbitrary pre-existing data)):
> CLEAR
> FROM <c> <d>
> WHERE {
> ?who knows ?whom .
> ?whom mbox ?mbox } }
I dont believe so, wouldn't
FROM <c> <d>
WHERE {
?who knows ?whom .
?whom mbox ?mbox }
Be equivalent to
FROM <c> <d>
WHERE {
SOURCE ?g1 { ?who knows ?whom } .
SOURCE ?g2 { ?whom mbox ?mbox } .
FILTER ?g1 = <c> || ?g1 = <d> &&
?g2 = <c> || ?g2 = <d> }
- Steve
Received on Thursday, 2 June 2005 08:44:43 UTC