W3C home > Mailing lists > Public > www-rdf-interest@w3.org > November 2000

Re: Of partial reification

From: Jonas Liljegren <jonas@rit.se>
Date: 23 Nov 2000 17:52:16 +0100
To: Graham Klyne <GK@Dial.pipex.com>
Cc: "ML RDF-interest" <www-rdf-interest@w3c.org>
Message-ID: <87y9yaeim7.fsf@astral.paranormal.se>
Graham Klyne <GK@Dial.pipex.com> writes:

> At 01:21 PM 11/23/00 +0100, Jonas Liljegren wrote:
> >Graham Klyne <GK@Dial.pipex.com> writes:
> >
> > >     [S] --rdf:Type-----> [rdf:Statement]
> > >     [S] --rdf:Subject--> [SomeResource]
> >
> >Heh!  This could be used as an alternative to having dedicated
> >variable URIs in queries.  The above would match all statements with
> >the specified subject.
> Something of the kind did occur to me...
> >But I still prefere having the varaiables...
> ... I can sympathize with that.
> But consider:
>    [?S] --rdf:type-------> [rdf:Statement]
>    [?S] --rdf:subject----> [SomeResource]
>    [?S] --rdf:predicate--> [?A]
>    [?S] --rdf:object-----> [?B]
> would match all resources that modelled statements about [SomeResource].
> What is the purpose of variables in such a query?

The variables is necessary if you want something two or more steps
away.  As in:

    [?S1] --rdf:type-------> [rdf:Statement]
    [?S1] --rdf:subject----> [SomeResource]
    [?S1] --rdf:predicate--> [?A]
    [?S1] --rdf:object-----> [?B]
    [?S2] --rdf:type-------> [rdf:Statement]
    [?S2] --rdf:subject----> [?B]
    [?S2] --rdf:predicate--> [type]
    [?S2] --rdf:object-----> [?C]

This woulb be used to get all the types of the resource properties.
And since we are using whole statements, we can transfer and store
them in a more compact manner.

/ Jonas Liljegren

The Wraf project http://www.uxn.nu/wraf/
Sponsored by http://www.rit.se/
Received on Thursday, 23 November 2000 11:51:03 UTC

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