W3C home > Mailing lists > Public > www-rdf-interest@w3.org > February 2002

Re: Provenance in RDF

From: Geoff Chappell <geoff@sover.net>
Date: Wed, 27 Feb 2002 15:54:31 -0500
Message-ID: <010d01c1bfd0$f4c41b00$0400a8c0@GSC866>
To: "Ronald Daniel" <rdaniel@interwoven.com>, "Dave Reynolds" <der@hplb.hpl.hp.com>, "RDF Interest \(E-mail\)" <www-rdf-interest@w3.org>
There are no assumptions in our system about whether the fourth member of
the quad (fourth in addition to the pred, subj, and obj that is) is a
statement id or a context id. In the site I referenced in my last email we
use it as a statement id (i.e. each statement has a unique id).

Our query language doesn't require the use of the quads but does allow its
use. Internally, our system is quad based. If the "context" isn't specified
in a query (i.e. a triple is used instead of a quad), we assume a  null
context (a particular well-known uri). A triple-based query only sees
statements in the null context (contrast that with conventional triple
refiication where queries are clogged with the machinary of reification -
the reifying statements themselves).

rdgs,

Geoff
----- Original Message -----
From: "Ronald Daniel" <rdaniel@interwoven.com>
To: "'Geoff Chappell'" <geoff@sover.net>; "Dave Reynolds"
<der@hplb.hpl.hp.com>; "RDF Interest (E-mail)" <www-rdf-interest@w3.org>
Sent: Wednesday, February 27, 2002 3:24 PM
Subject: RE: Provenance in RDF


> Geoff,
>
> I've heard the term 'quad' used a couple of different ways.
> I assume you mean it as "a triple plus an ID", but it would
> be good if you could confirm or correct that.
>
>
> Thanks,
> Ron Daniel Jr.
> Standards Architect
> Interwoven, Inc.
> 803 11'th Ave.
> Sunnyvale, CA, USA  94089
> Tel: 408 530 5922
> Cell: 925 368 8371
> Email: rdaniel@interwoven.com
>
> Visit www.interwoven.com
> The Leader in Enterprise Content Management
>
> > -----Original Message-----
> > From: Geoff Chappell [mailto:geoff@sover.net]
> > Sent: Wednesday, February 27, 2002 11:28 AM
> > To: Dave Reynolds; RDF Interest (E-mail)
> > Subject: Re: Provenance in RDF
> >
> >
> >
> > ----- Original Message -----
> > From: "Dave Reynolds" <der@hplb.hpl.hp.com>
> > To: "RDF Interest (E-mail)" <www-rdf-interest@w3.org>
> > Sent: Wednesday, February 27, 2002 7:14 AM
> > Subject: Provenance in RDF
> >
> >
> > > We are working on a semantic web related application that needs some
> > provenance
> > > support. We have various routes for doing this but would be
> > interested in
> > > hearing of other's experiences. Are there any groups out
> > there that have
> > > developed applications supporting provenance within RDF
> > that would be
> > willing to
> > > share their experiences on what worked well or badly?
> > >
> > [...]
> > >
> > > Dave
> >
> > We put up a site to test this and other issues a while back
> > (http://www.intellidimension.com/itdsw/default.asp). The
> > source and time is
> > stored for each statement and statement visibility to queries
> > is controlled
> > by rules (i.e. if the statement comes from a source you
> > trust, you see it --
> > {?p ?s ?o} <- {[x:sourceOf] ?source {?p ?s ?o}} and {[x:trusts]
> > [x:CurrentUser] ?source}.
> >
> > We started with conventional triple-based reification (1 statement = 4
> > triples + provenance triples) but moved to a quad
> > representation internally
> > for performance reasons (1 statement = 1 quad + provenance triples).
> > Performance was workable with triple reification but much
> > improved with
> > quads.
> >
> > Geoff
> >
Received on Wednesday, 27 February 2002 15:54:02 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:53 GMT