Sigge, I'm afraid that any discussion on application profiles, which is going
to satisfy the requirements which you've listed, will become technical.
I also don't want to keep harping on XML Schema but it allows you to do more
than "extension elements and specialized qualifiers and encoding schemes". I
think that it could probably provide a solution to most of the significant
things which people want to do with "application profiles" including those you
listed:
- narrowing semantics through derivation by restriction;
- providing readable labels and descriptions through appinfo and documentation
tags;
- enabling deletion, merging and creation of new elements.
But there are some problems. In order to import elements and types from the dc
namespace, it requires an XML Schema for the DCES to be defined in the dc
namespace and this doesn't currently exist. It is also quite complex for new
users but example schemas can overcome this to some extent. It is also not yet
a stable W3C Recommendation but the XML Schema WG are hoping it will go to
Candidate Recommendation in September.
If the requirements for 'application profiles' could be clearly specified with
the help of examples, then I'd be happy to write up a document or work with
others to show how you can or cannot satisfy these requirements using XML
Schema.
regards,
jane
+----------------------------------+---------------------------------------+
| Dr Jane Hunter | Senior Research Scientist |
| DSTC Pty Ltd | Distributed Systems Technology CRC |
| Level 7, General Purpose South | Tel : +61 7 3365 4310 |
| The University of Queensland | Fax : +61 7 3365 4311 |
| Queensland 4072, Australia | Email : [log in to unmask] |
+----------------------------------+---------------------------------------+
> In my view, this applications profiles discussion has become much too
> technical. From the point of view of a software engineer (using XML
> parser or RDF processor), Jane's assertion is correct, that such a
> profile basically is "a schema which imports elements from existing
> community-defined namespaces or other schemas".
>
> However, there is more to it than that. Pricilla states "an
> application profile is a bit more than just mixing and matching
> elements from different namespaces. It also includes specifying
> conventions and constraints on usage that may not exist in the vanilla
> namespace", and then gives examples that pretty much looks like
> cataloging rules to me. Appart from extension elements and specialized
> qualifiers and encoding schemes, applications profiles may do
> significant things
>
> - impose conventions narrowing the semantics of elements or constrain
> their values. People do so without using element qualification or
> explicit encoding schemes.
>
> - use readable lables and descriptions for elements and vocabularies
> which differs from those devised by the DCMI. People do so in order to
> adapt the element set for certain purposes or target audiences, or
> just for making them suit the cataloging rules their using.
>
> - delete or merge DC elements. For many purposes you don't need 15
> elements. Also, people do things like merging Contributor with
> Creator. Quite a few implementors have abandoned "Source" in favour of
> dcq:isbasedon (which, perhaps unfortunately didn't pass the dc-usage
> committee).
>
>
> Sigge
>
> ________________
> Sigfrid Lundberg, Ph.D., . [log in to unmask]
> Lund University Library, http://www.lub.lu.se/~siglun/
> Netlab, PO Box 3, S-221 00 Lund phone +46 (0)46 222 36 83
>
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