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Carrying all of a resource's metadata as RDFa?

From: Hondros, Constantine <Constantine.Hondros@wolterskluwer.com>
Date: Thu, 29 Oct 2009 12:01:16 +0100
To: "public-rdfa@w3.org" <public-rdfa@w3.org>
Message-ID: <6C01B6D23EB50A4487054D57249A0B010966A8B57A@EUSRVWK01005.eu.wkeurope.com>
We know that RDFa can be used very effectively to semantically tag content that already exists within a resource - for example, a text node within an XHTML document tree.

But what if you want to carry ALL of a resource's metadata within it as RDFa, even though that metadata has object literals that should not be visible within the rendered document? Something like this might be worthwhile if you want to simplify the creation and delivery of content + metadata by merging it in a single XHTML resource.

For example, let's say we want the following RDF - basically defining a date-range in which a resource is "applicable" - to be carried within the same resource that it refers to:

    <>  xyz:applicablePeriod  _:a .
    _:a  rdf:type  xyz:Period
    _:a  xyz:startDate "blah"^^rdf:XMLLiteral
    _:a  xyz:endDate  "blah"^^rdf:XMLLiteral

This suffers from two problems:
1. you need some sort of nested element structure to code this
2. the object literals (XMLLiteral, just for the sake of argument) must not display within the rendered document

It would seem logical to put this sort of metadata in the <head> of a document, but since that only allows a flat structure it seems to be impossible with RDFa. On the other hand, you could put it in a dedicated <div> / <span> structure, but then you are forced to add content to the document that you do not want to display.

    <div rel="xyz:applicablePeriod">
         <span typeof="xyz:Period">
              <span property="xyz:startDate" datatype="rdf:XMLLiteral">blah</span>
              <span property="xyz:startDate" datatype="rdf:XMLLiteral">blah</span>
         </span>
    </div>

Any thoughts on this? I can understand it if it's considered an abuse of RDFa to try to carry arbitrary metadata, but part of the attraction of RDFa for me is the idea of avoiding having to create a parallel .rdf file resource for a resource by carrying all metadata as RDFa.

Thanks for comments,
Constantine

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Received on Thursday, 29 October 2009 11:03:55 UTC

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