Interesting...
It's certainly interesting to compare, I'd love to hear people's
opinions on this.
What happens to DC-XML-min in this context? Can it be reasonably defined
as a subset of this?
/Mikael
tor 2007-07-19 klockan 11:15 +0100 skrev Pete Johnston:
> Bruce D'Arcus (I think) suggested a while back that rather than
> designing a new XML format for the DCAM description model, we should
> consider using a restricted profile of RDF/XML that played reasonably
> well with some XML schema languages.
>
> With the previous version of the DCAM, I think this was slightly
> problematic for various reasons, mainly because the DCAM concept of
> value string didn't map particularly cleanly into RDF's concept of
> literal. In the recent revision of the DCAM, we tried to address that
> problem, and as a result the mapping from the DCAM description model to
> the RDF graph [1] is much more straightforward.
>
> So I think maybe that better alignment means that we could/should also
> consider the "DC-XML as profile of RDF/XML" option.
>
> I've created a set of RDF/XML examples using a subset of the constructs
> in RDF/XML:
>
> http://www.incognitum.net/petej/projects/dc-xml/dc-rdfxml/xml/2007/06/19
> /
>
> They correspond (I hope) to the DC-XML-Full examples listed at
>
> http://dublincore.org/architecturewiki/DCXMLRevision/DCXMLFInstances/200
> 7-06-19
>
> I haven't got as far as writing up a full description of that profile
> but the mapping is roughly:
>
> 1. DCAM Description Set -> RDF-XML Document Element
>
> 2. DCAM Description -> RDF-XML Node Element
>
> 2.1 DCAM ResourceURI -> RDF-XML Node Element/@rdf:about
>
> 3. DCAM Statement -> RDF-XML Property Element
>
> 3.1 DCAM Property URI -> RDF-XML Property Element Qname
>
> 4. DCAM Value Surrogate:
>
> 4.1 DCAM Literal Value Surrogate:
>
> 4.1.1 DCAM Value String
>
> DCAM Plain Value String:
> RDF-XML Property Element content +
> DCAM Language Tag: RDF-XML Property Element/@xml:lang
>
> DCAM Typed Value String:
> RDF-XML Property Element content +
> DCAM SES URI: RDF-XML Property Element/@rdf:datatype
>
> DCAM Typed Value String (XML Literal):
> RDF-XML Property Element content +
> RDF-XML Property Element/@rdf:parseType="Literal"
>
> 4.2 DCAM Non-Literal Value Surrogate:
>
> 4.2.1 DCAM Value URI -> RDF-XML Property Element/RDF-XML Node
> Element/@rdf:about
>
> 4.2.2 DCAM VES URI -> RDF-XML Property Element/RDF-XML Node
> Element/@dcam:memberOf
>
> 4.2.3 DCAM Value String
>
> DCAM Plain Value String:
> RDF-XML Property Element/RDF-XML Node Element/rdf:value content
> + (optional)
> DCAM Language Tag: RDF-XML Property Element/RDF-XML Node
> Element/rdf:value/@xml:lang
>
> DCAM Typed Value String:
> RDF-XML Property Element/RDF-XML Node Element/rdf:value content
> +
> DCAM SES URI: Property Element/RDF-XML Node
> Element/rdf:value/@rdf:datatype
>
> DCAM Typed Value String (XML Literal):
> RDF-XML Property Element/RDF-XML Node Element/rdf:value content
> +
> RDF-XML Property Element/RDF-XML Node
> Element/rdf:value/@rdf:parseType="Literal"
>
> 5. Description of Value with no Value URI:
> RDF-XML Property Element/RDF-XML Node Element/@rdf:nodeID
>
> and
>
> RDF-XML Node Element/@rdf:nodeID
>
> Notes:
>
> 1. In 4.2, using the "nested" Node Element makes it verbose, but I can't
> see how else to handle the combination of on the one hand encoding a
> non-literal value surrogate with only a value URI, no VES URI or value
> string, and on the other encoding a non-literal value surrogate with
> both a value URI and a value string, and using the same "pattern" for
> both cases (though if we decided to support only a subset of the DCAM
> description model, it could probably be simplified).
>
> There's (a first cut at) a RELAX NG Schema
>
> http://www.incognitum.net/petej/projects/dc-xml/dc-rdfxml/relax/2007/06/
> 19/dcrdfxml.rng
>
> I've done some work on some W3C XML Schemas and I'll tidy them up if
> it's worth pursuing this approach further.
>
> There may well be other mappings/patterns which can be used to generate
> a profile which is structurally simpler. Essentially, though, I think
> even this approach still involves a level of structural complexity in
> the XML not dissimilar to that of the other suggestions - and that's a
> consequence of the structural complexity of the DCAM description model
> itself. If we need to distinguish several different components in that
> "abstract" structure then we'll need a corresponding set of distinctions
> in the structure of the XML tree.
>
> Pete
>
> [1] http://dublincore.org/documents/2007/06/04/dc-rdf/
>
> ---
> Pete Johnston
> Technical Researcher, Eduserv Foundation
> Web: http://www.eduserv.org.uk/foundation/people/petejohnston/
> Weblog: http://efoundations.typepad.com/efoundations/
> Email: [log in to unmask]
> Tel: +44 (0)1225 474323
>
--
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Plus ça change, plus c'est la même chose
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