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"Overriding" Attribute Declarations

From: Eliot Kimber <ekimber@innodata-isogen.com>
Date: Tue, 12 Jun 2007 00:11:19 -0400
Message-ID: <466E1CE7.6070009@innodata-isogen.com>
To: <xmlschema-dev@w3c.org>

In XML DTDs, one can override the declaration of an attribute declared 
in an external declaration set by declaring the overriding version 
earlier, e.g.:

<!DOCTYPE foo SYSTEM "mybase.dtd" [
<foo bar="baz/>

Where mybase.dtd declares the element type "foo" with the attribute bar 
with a different type.

I don't see an obvious way to do with with XSD using redefine. At least, 
when I add a declaration to a redefine that otherwise works (to add a 
new attribute not declared in the base type being redefined), Xerces 2.9 
says I have a duplicate attribute declaration.

I didn't see anything about this specifically in the XSD Primer and I'm 
afraid I find the formal definition largely impenetrable (at least at 
this late hour).

Have I missed something?

Note, in my specific case I don't have control over the base schemas, so 
I can't do something like pull the attributes to be redefined out into 
their own attribute group, although I'm not sure that would solve the 


W. Eliot Kimber
Professional Services
Innodata Isogen
8500 N. Mopac, Suite 402
Austin, TX 78759
(214) 954-5198

Received on Tuesday, 12 June 2007 04:11:55 UTC

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