W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > October to December 2004

Re: UNSAID - two test cases

From: Dan Connolly <connolly@w3.org>
Date: Wed, 22 Dec 2004 08:27:45 -0600
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <1103725665.3082.680.camel@dirk>

On Wed, 2004-12-22 at 10:26 +0000, Seaborne, Andy wrote:
[...]
> ==== Case 1: selecting a resource based on the absence of a type triple:
> 
> An example like this has just been asked on jena-dev.
> 
> "Find all the things that are not of a given class."

Please let's be *very* careful about negation vs. UNSAID.
This query does *not* find all the things that are
not of a given class. It finds things that are not
stated (directly, i.e. by way of rdf:type) in the input data
to be of a given class.

> == Query 1:
> PREFIX : <http://example.org/ns#>
> 
> SELECT ?r
> WHERE (?r rdf:type ?type)        # Get all the things with a type
>        UNSAID (?r rdf:type :foo)

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Wednesday, 22 December 2004 14:27:12 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:21 GMT