Re: alternate identifier draf

I was looking at the 

http://www.w3.org/community/schemabibex/wiki/Identifier-2

again and I am a little bit worried about the complexity that the user may face. At this moment, the RDFa encoding says:

<div typeof="Book">
  ...
  <span property="publisher">Hal Leonard</span>
  <span property="identifier" typeof="Identifier">
      (<span property="name">HL.114335</span>)
      <span property="issuedBy">Hal Leonard</span>
  </span>
</div>

(I noticed that the wiki does not have the 'publisher' property any more. Any reason for this? That is why I added here)

At the moment, the Identifier type contains only two properties: 'name' and 'issuedBy'. But there may be more in future (I am not a librarian, so I cannot give an example, but I could imagine additional metadata on the type of identifiers used in a particular file). If that was the case, it would mean to repeat quite a lot of things of the kind:

<div typeof="Book">
  ....
  <span property="identifier" typeof="Identifier">
      (<span property="name">HL.114335</span>)
      <span property="issuedBy">Hal Leonard</span>
      <span property="inStandard">ISBN</span>
      <span property="somethingElseOnHalIdentification">something</span>
  </span>
</div>

This may become a pain if the same page contains lots of library items following the same patterns.

Fortunately, both microdata and the new (and coming) RDFa+HTML5 include a possibility to reduce these repetitive structures. In microdata this is called @itemref; in RDFa+HTML5 it will be called property copying[1]. Using the RDFa syntax this is what one could do:

<div resource="#IDcharacteristics" typeof="rdfa:Pattern">
   <span property="issuedBy">Hal Leonard</span>
   <span property="inStandard">ISBN</span>
   <span property="somethingElseOnHalIdentification">something</span>
   ...
</div>
...
<div typeof="Book">
  ....
  <span property="identifier" typeof="Identifier">
      (<span property="name">HL.114335</span>)
      <link property="rdfa:copy" href="#IDcharacteristics"/>
  </span>
</div>
<div typeof="Book">
  .... Data for another book
  <span property="identifier" typeof="Identifier">
      (<span property="name">HL.XYZ</span>)
      <link property="rdfa:copy" href="#IDcharacteristics"/>
  </span>
</div>

etc.

I did not want to add this to the Wiki, because I am not sure it is of interest (right now the Identifier structure has only two properties, ie, there would be no gain). But it may be of interest for other cases, too.

If there is an interest I am happy to convert this into microdata using @itemref, too.

I hope this helps...

Ivan 

[1] http://www.w3.org/2010/02/rdfa/sources/rdfa-in-html/Overview-src.html#property-copying

----
Ivan Herman, W3C Semantic Web Activity Lead
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mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf