- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Fri, 28 Jan 2005 14:58:57 +0000
- To: Phil Dawes <pdawes@users.sf.net>
- Cc: public-rdf-dawg-comments@w3.org
Phil Dawes wrote:
> Hi Andy
>
> Seaborne, Andy writes:
> > Phil Dawes wrote:
> > >
> > > I don't understand this - isn't ?label bound to the set of all URIs
> > > and literals that match the regex '*foo*'?
> >
> > Not in any implementation I know of - there is no access to the set of all URIs
> > and literals. RDF is only triples.
> >
> > Is this query valid to you?
> >
> > select ?label
> > where (?label LIKE "%foo%")
> >
>
> In veudas - yes.
> This is triples - i.e. the set of virtual triples that match:
> (?label LIKE "%foo%").
> e.g. ("foobah" LIKE "%foo%") ("foot" LIKE "%foo%").
>
> It's not RDF though, since ?label can match literals. Actually
> 'LIKE' has domain 'literal' in the veudas query engine, so you'd only
> get literal results to this query.
>
> Literal subjects work fine within veudas internals, not really by
> design, but simply because the store layout doesnt restrict this.
>
> But thanks - this does explain to me why sparql needs the AND clauses.
>
> Out of interest, if RDF did move to allow literals as subjects, would
> this remove the necessity for AND?
Somewhat. Not all constraints are binary predicates. And it can be
inconvenient to write "?x + 3 < 2 * ?y" out in triples.
Andy
>
> Thanks again,
>
> Phil
>
>
>
Received on Friday, 28 January 2005 14:59:09 UTC