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Re: Named Graph Homepage - second draft

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 8 Apr 2004 08:26:44 +0300
Message-Id: <52F2156C-891D-11D8-8097-000A95EAFCEA@nokia.com>
Cc: <www-archive@w3.org>, "ext Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "Pat Hayes" <phayes@ihmc.us>
To: "ext Chris Bizer" <chris@bizer.de>


On Apr 07, 2004, at 17:10, ext Chris Bizer wrote:

> Hi,
>
> I updated the draft for the Named Graph homepage and included the 
> comments
> from Patrick and Jeremy. I also added RDF/XML as a third possible 
> syntax for
> Named Graphs to section 3:
>
> 3.3 RDF/XML
>
> A collection of RDF documents can be seen as a set of Named Graphs. 
> This
> gives Named Graphs upward compatibility with RDF/XML, but has the
> disadvantage that retrieval URL, document name and graph name are 
> mixed up.

I've been chewing on this a bit more recently, and I still think that it
makes alot more sense to derive the name of an RDF/XML encoded graph 
based
on the xml:base value *of the root <rdf:RDF> element*.

Yes, it is true that any element in the RDF/XML can have its own 
xml:base
attribute defined, but there can be at most one such attribute defined
for the <rdf:RDF> element, so there's no ambiguity there.

And since the xml:base value need have no correlation to the URI via 
which
the RDF/XML instance was obtained, we avoid the URI denotation ambiguity
otherwise introduced by taking the access URI as denoting the graph.

Otherwise, I'd prefer to simply state that there is no obviously correct
and reliable means to associate a graph name URI with an RDF/XML 
instance
in the instance itself, and avoid (being misunderstood) proposing that
the access URI be used (which I think is a mistake/hack/etc.).

Thus,

<rdf:RDF xml:base="http://example.org/foo" ...>
    ...
    <rdf:Description xml:base="http://example.org/bar" ...>
    ...
</rdf:RDF>

equates to

<http://example.org/foo> {
    ...
}

Note that the second xml:base on the description element has
no affect on the name of the graph.

Also, this works even when mulitiple RDF/XML fragments are
embedded in the same e.g. XHTML document, since each root
<rdf:RDF> element can have its own xml:base value and hence
a distinct name.

We'd restrict the interpretation of xml:base to explicit
attributes occurring on the root <rdf:RDF> element, not
inherited from a higher XML scope.

Eh?

Patrick



>
> Chris
> <NamedGraphsPage.zip>

--

Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com
Received on Thursday, 8 April 2004 01:26:53 GMT

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