- From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
- Date: Wed, 28 Jul 2004 16:31:54 +0100
- To: public-rdf-dawg@w3.org
On Wed, Jul 28, 2004 at 11:14:17AM -0400, Eric Prud'hommeaux wrote:
> ===== Executing a Federated Query =====
>
> To date, my implementations are more simple than the efficient. The
> first query returns a set of results and the second query is
> iteratively performed for each of those results, ala:
>
> result of first query:
> +--------------------------+
> | ?mbox |
> +--------------------------+
> | <mailto:sue@example.com> |
> | <mailto:ann@example.com> |
> | <mailto:joe@example.com> |
> | <mailto:frd@example.com> |
> | <mailto:pat@example.com> |
> +--------------------------+
>
> following queries:
> ?w foaf:mbox <mailto:sue@example.com>.
> ?w foaf:depiction ?pic.
In BRQL I think you could write:
SELECT ?pic
WHERE (?w foaf:mbox ?mb)
(?w foaf:depiction ?pic)
AND ?mb == <mailto:sue@example.com> ||
?mb == <mailto:ann@example.com> ||
?mb == <mailto:joe@example.com> ||
?mb == <mailto:frd@example.com> ||
?mb == <mailto:pat@example.com>
Which would save the roundtrips.
- Steve
Received on Wednesday, 28 July 2004 11:31:57 UTC