[tdwg-tapir] Output model definition and mixed name spaces.

Renato De Giovanni renato at cria.org.br
Mon Jan 2 22:57:27 CET 2006


Hi Roger,

You're right about the way of producing an output with mixed 
namespaces (defining all XSDs and importing them into the main one). 
The "xsd:import" tag is not part of what we called the "basic schema 
language" (the subset of XML Schema that needs to be understood by 
TAPIR provider implementations if they want to be able to interpret 
custom output models). But it's an optional feature - and a quite 
interesting one, I agree.

Since mapping uses XPath to identify nodes in the output model, 
unless I'm missing some point it should be possible, for instance, to 
map some concept to this node from your example:

/rdf:RDF/rdf:Description/dc:creator/rdf:Description/vCard:FN

Whether the output definition language used by TAPIR was a "good" 
choice or not, that's another issue. I'm no big fan of XML Schema and 
I do agree that it is quite complex (that's why we needed to specify 
a subset of it as the "basic schema language"). But DiGIR was already 
using it to define "record structures", and all output models from 
the TDWG community have an XML Schema ready to be used, unlike your 
example.

Anyway, if you have any other suggestion of a better or easier way to 
specify output models, I'm certainly interested to know, regardless 
being too late or not to make such a change in the first version of 
TAPIR. Personally I've always liked the idea of making TAPIR 
independent of the output language (capabilities responses would say 
"I understand this and that output languages defined in these 
locations"), but that would probably be a drastic change at this 
time. 

Regards,
--
Renato

On 30 Dec 2005 at 10:51, Roger Hyam wrote:

> Hi Everyone,
> 
> In the few days between Christmas and New Year I am doing some thinking 
> about architecture and the general problem of validating (controlling) 
> data alongside using a more RDF based approach. This is an open world / 
> closed world problem really but relates to Tapir as follows. Suppose I 
> want to specify an output model like this:
> 
> <?xml version="1.0"?>
> <rdf:RDF xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>          xmlns:dc="http://purl.org/dc/elements/1.1/"
>          xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
>          xmlns:vCard = "http://www.w3.org/2001/vcard-rdf/3.0#">
> <rdf:Description> 
> <dc:creator>              
>  <rdf:Description rdf:about = "http://qqqfoo.com/staff/corky" >
>   <rdfs:label> Corky Crystal </rdfs:label>
>   <vCard:FN> Corky Crystal </vCard:FN>
>   <vCard:N rdf:parseType="Resource">
>     <vCard:Family> Crystal </vCard:Family>
>     <vCard:Given>  Corky </vCard:Given>
>     <vCard:Other>  Jacky </vCard:Other>
>     <vCard:Prefix> Dr </vCard:Prefix>
>   </vCard:N>
>   <vCard:BDAY> 1980-01-01 </vCard:BDAY>
>  </rdf:Description>
> </dc:creator>
> </rdf:Description> 
> </rdf:RDF>
> 
> This is taken from: http://dublincore.org/documents/dcq-rdf-xml/#sec3 
> and is a good example or using a mix of 'other' vocabularies to describe 
> something. DublinCore and vCard are pretty standard and should really 
> not be re-invented.
> 
> I can't see how to define this structure in a simple XML Schema. It only 
> allows a single target namespace so one needs to have at least 4 XSD 
> documents (1 + 3 imported) to define this tightly. Here is an example of 
> how to do this kind of thing:
> 
> http://www-128.ibm.com/developerworks/xml/library/x-tipschnm.html
> 
> We have the additional problem that there aren't actual public XML 
> Schema definitions of these things so one would have to make up schemas 
> defining the elements used. It all gets quite horrible.
> 
> Does the subset of XML Schema in Tapir support imports?
> 
> Tapir has the intention of combining separate 'concepts' (which implies 
> different namespaces) into a single output model but do the concepts all 
> have to be mapped into a single namespace to make the thing workable?
> 
> I may be missing something obvious with XML Schema or Tapir (or both) in 
> which case I would be grateful if some one could set me right. I will 
> blame it all on an excess of rich food and red wine over the past few days.
> 
> Many thanks for your thoughts.
> 
> Happy New Year,
> 
> Roger





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