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Re: requesting XML records

From: Andy Powell <a.powell@ukoln.ac.uk>
Date: Thu, 27 Mar 2003 12:00:35 +0000 (GMT)
To: Jonathan Rowell <bigrat18@hotmail.com>
cc: www-zig@w3.org
Message-ID: <Pine.SO4.4.05.10303271147370.10308-100000@lamin.ukoln.ac.uk>

On Thu, 27 Mar 2003, Jonathan Rowell wrote:

> HI Andy!
> 
> All I was trying to ensure was that, when I ask for XML to be returned in 
> some format, the data returned says what it is.

Sure.

> Currently when I query a Z.39.50 server I have to know the character set and 
> data format. Indeed when I go to the Bavarian server on one port I get MAB2 
> and on the other I get UniMarc - effectively two servers.
> 
> Now wouldn't it be wonderful that the XML data returned, which almost 
> certainly will be in some character set supported by all parsers, I get an 
> XML document which says "I am MAB2" or "I am NorMarc" or "I am USMarc21". 
> The simplest and easiest way of doing this is to include a namespace 
> (default) declaration.

...except that for many metadata record formats multiple namespaces will
be required.

> I know what will happen if I get a DTD or Schema reference or nothing at 
> all. Oh, they'll say, we're almost conformant with that, or, we changed that 
> last week, or whatever.

If the XML metadata record validates against the schema then it is valid
record according to the record format that is associated with
that schema ('NorMARC', 'USMarc21', or whatever).  If it doesn't validate,
then it isn't conformant.

The point is that complex metadata applications (record formats) will use
multiple namespaces, therefore you have to indicate the record format
using a schema - not using one of the namespaces.

> If USMarc21 can do something like this, why not everybody else? 
> xmlns="http://www.loc.gov/MARC21/slim"

A namespace is simply a way of grouping (i.e. managing) a collection of
names.  LoC may have chosen to put all MARC21 names into a single
namespace but there is absolutley no requirement on them to have done this
(they could have chosen to give each element its own name) and in lots of
situations it is much easier to manage your names over time if you use
multiple namespaces - because you can then manage smaller groupings of
names.

DC, ODRL, CreativeCommons are all examples of metadata applications that
have chosen to use multiple namespaces - I'm sure there are lots of
others.

Andy.

> Jonathan
> 
> PS: slim = Slim Shady?
> 
> >From: Andy Powell <a.powell@ukoln.ac.uk>
> >To: Mike Taylor <mike@indexdata.com>
> >CC: www-zig@w3.org
> >Subject: Re: requesting XML records
> >Date: Wed, 26 Mar 2003 23:27:17 +0000 (GMT)
> >
> >
> >On Wed, 26 Mar 2003, Mike Taylor wrote:
> >
> > > I don't pretend to understand all the back-and-forthing of this stuff,
> > > and you very probably have a deeper understanding of it than I do.
> > > But what's clear is that the concept we're trying to capture in the
> > > putative "give me an XML record in this schema" request is _not_
> > > talking about getting back records "in a specified namespace" -- if
> > > that phrase even means anything.
> >
> >I agree.  What is being requested is a record that conforms with a
> >particular 'XML application'... and the application is defined by an XML
> >schema, not by an XML namespace.
> >
> >Andy
> >--
> >Distributed Systems, UKOLN, University of Bath, Bath, BA2 7AY, UK
> >http://www.ukoln.ac.uk/ukoln/staff/a.powell       +44 1225 383933
> >Resource Discovery Network http://www.rdn.ac.uk/
> >
> >
> 
> 
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> 

Andy
--
Distributed Systems, UKOLN, University of Bath, Bath, BA2 7AY, UK
http://www.ukoln.ac.uk/ukoln/staff/a.powell       +44 1225 383933
Resource Discovery Network http://www.rdn.ac.uk/
Received on Thursday, 27 March 2003 07:00:39 GMT

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