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Re: Absolute IRIs (Was: Re: IRI guidance)

From: Eric Prud'hommeaux <eric@w3.org>
Date: Mon, 2 May 2011 13:27:46 -0400
To: Alex Hall <alexhall@revelytix.com>
Cc: Ivan Herman <ivan@w3.org>, "nathan@webr3.org" <nathan@webr3.org>, RDF WG <public-rdf-wg@w3.org>
Message-ID: <20110502172745.GA29704@w3.org>
* Alex Hall <alexhall@revelytix.com> [2011-05-02 11:44-0400]
> On Fri, Apr 29, 2011 at 2:28 PM, Ivan Herman <ivan@w3.org> wrote:
> 
> >
> >
> > On 29 Apr 2011, at 19:50, Eric Prud'hommeaux <eric@w3.org> wrote:
> > >
> > > I'm not personally keen on this absolute IRI restriction. I included
> > > it in this proposal in order to minimize the permutations being
> > > examined at once ("minimal change"). For usability, I find
> > >  Data:
> > >    <s> <p> <o> .
> > >  Query:
> > >    ASK { ?s <p> ?o }
> > >
> > > very intuitive when you don't have to specifically call out a base
> > > URI. Using IRI references instead of IRIs would permit the above query
> > > to work in e.g. Jena (which currently presumes absolute IRIs).
> > >
> >
> 
> Is there a need for this outside the context of illustrating some simple
> test data and queries?

It's really just a minor usability/simplicity point. The Direct
Mapping of Relational Data to RDF maps a relational database to an RDF
graph with all relative IRIs. Custodians of the data can treat it as
they would a tarball of HTML docs in a filesystem, where the access,
be it e.g. HTTP backed by some Apache configuration, or directly via
file://localhost IRIs, determines the base. Like the browser's ability
to navigate relative links, SPARQL queries can elide the base,
matching RDF graphs regardless of access. When it doesn't work, I'd
say it's a usability obstacle a little worse than issue 18 .


> > Do you mean that the RDF concepts should allow relative URI-s (well, IRI-s)
> > in Graphs? That might be a pretty major change in RDF; what would
> > dereferencing mean? Where would the base come from? Would two graphs with
> > different bases but otherwise identical relative IRI-s be identical? Etc...
> >
> > Do we have a convincing use case to engage into this?
> >
> 
> I agree -- allowing relative IRIs in the abstract syntax is a potentially
> far-reaching change which I am personally opposed to.  I think it's worth
> sacrificing a little bit of convenience on the part of a document author in
> order to gain the consistency that absolute IRIs provide in terms of
> preserving the meaning of a graph.
> 
> -Alex
> 
> 
> 
> >
> > Ivan

-- 
-ericP
Received on Monday, 2 May 2011 17:28:19 GMT

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