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Are Schema import statements transitive?

From: <Simon.Cox@csiro.au>
Date: Fri, 26 Apr 2002 09:44:38 +0800
Message-ID: <116D27C8E12BD411B3AB00B0D022B0B8010E5601@yate.wa.csiro.au>
To: xmlschema-dev@w3.org
Cc: rmartell@galdosinc.com

It appears that import statements in schemas 
are NOT transitive. For example, consider
the following situation:

     import        import
A ----------> B ---------> C

We had assumed that schema A will automatically
also import schema C (in fact, some parsers appear to behave in
this way). But apparently this is not the specified behavior. One
of the Xerces developers first brought this to our attention, and a
closer reading of the XML Schema spec seems to corroborate this:

Section 4.2.3 of Part 1 (Structures) states the following with
respect to referencing schema components across namespaces:

"Two things are required: not only a means of addressing such
foreign components but also a signal to schema-aware processors
that a schema document contains such references..."

The <import> statement is the signal, of course. This seems to imply
that schema A above would also have to import schema C. 

Can anyone else shed some light here?

[This mail represents part of a discussion of work in progress 
and should not be used for any purpose without my permission.] 
Simon.Cox@csiro.au  CSIRO Exploration & Mining
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PO Box 1130, Bentley WA 6102  AUSTRALIA
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Received on Thursday, 25 April 2002 22:10:04 UTC

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