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Re: A reason for dropping seperate AND clauses

From: Phil Dawes <pdawes@users.sf.net>
Date: Fri, 28 Jan 2005 14:31:03 +0000
Message-ID: <16890.19623.836624.973983@gargle.gargle.HOWL>
To: andy.seaborne@hp.com
Cc: public-rdf-dawg-comments@w3.org

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?

Thanks again,

Phil
Received on Friday, 28 January 2005 14:29:37 GMT

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