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Schema components and namespaces

From: Richard E. Rathmann <Richard.Rathmann@noaa.gov>
Date: Thu, 24 Feb 2000 11:47:20 -0500
Message-Id: <4.1.20000224105724.00a28850@mailsrv.csc.noaa.gov>
To: www-xml-schema-comments@w3.org

I'm currently working on my first schema, and I think I have come across a few
things that I feel I need clarification within the XML Schema Part 1:
Structures Working Draft.  

First, according to Section 4.2.2, References to schema components across
namespaces, of the 17 December 1999 Draft:

>We declare the "ref" attribute on <group>, <element> and <attributeGroup>, 
>the "type" attribute on <element> and <attribute> and the "source" attribute 
>on <type> and <datatype> to be of type QName. Use of prefixes in such 
>attributes is governed by the normal rules for QNames, i.e. that there must 
>be a namespace declaration for the prefix in scope; 

 From this statement, correct me if I'm wrong, I would assume that any of these
QNames not containing a namespace prefix would therefore belong to the default
namespace.  However, since the examples within the Schema Structures WD qualify
neither the names of the schema elements nor the "ref", "type", and "source"
attribute values with prefixes, this would seem to say that all the referenced
declarations belong to the "http://www.w3.org/1999/XMLSchema" namespace.

Second, in trying to include the "type" and "href" attributes from the XLink
namespace on elements defined for a different namespace I ran into a bit of a
stumbling block.  Since these attributes belong to a different namespace than
my targetNS, they must be referenced from an imported schema for the XLink
namespace, correct?  However, the WD does not allow the "ref" attribute on
attribute declaration elements.  Am I correct in assuming, therefore, that the
only way to accomplish my goal would be to create my own XLink namespace schema
which declares these attributes within an <attributeGroup> element with the
"attributeSpec"s I require for my document type?  If so, the Schema WD would
therefore seem to promote the possibility of people creating their own schemas
and imply that they conform to a given specification like XLink by using the
associated namespace with the spec as the targetNS, yet this may or may not be

Thanks, in advance, for any clarification anyone might give,
Richard Rathmann

Richard E. Rathmann
TPMC Web Designer at the NOAA Coastal Services Center
2234 South Hobson Avenue  ~  Charleston, SC  29405-2413
(843) 740-1314 (voice)  ~  (843) 740-1224 (fax)
Richard.Rathmann@noaa.gov (e-mail)  ~  http://www.csc.noaa.gov (web)

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Received on Thursday, 24 February 2000 11:48:07 UTC

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