RE: [ubl-dev] Customising and versioning

["Stephen Green" <stephen_green@bristol-city.gov.uk>]

Excellent. 

I guess UBL would have to be quite brave to implement such a mechanism though.

All the best

Steve


>>> "David RR Webber (XML)" <david@drrw.info> 11/09/06 14:14:07 >>>
Stephen,
 
Should be very straightforward in CAM - since is operates on the resulting wellformed XMl instances - you merely provide the deltas of the structure elements as choices and use the "when" switch contextually to select the tree structure you want - including and excluding elements / attributes as needed.
 
Plus - in the latest release of CAM we've implemented an unordered mechanism - that allows you to be more "fuzzy" about the structure too - giving you the ability to have fault tolerant validation when your trading partner has done some extensions that are valid but perhaps you did not have that pre-configured on your side.
 
DW




-------- Original Message --------
Subject: RE: [ubl-dev] Customising and versioning
From: "Stephen Green" <stephen_green@bristol-city.gov.uk>
Date: Mon, September 11, 2006 8:45 am
To: <ubl-dev@lists.oasis-open.org>

How does this sound as a potential mechanism for use
of W3C XML Schema for minor versioning? I've never
heard it being used but it just seems to be the natural
consequence of W3C XML Schema derivation mechanisms.
1.
Use xsd:redefine for types (the namespace staying the
same by virtue of absence of minor version identifier)
then
2. 
Base minor version elements on these redefined types
but base them too, using xsd:substitutionGroup, on
the original major version elements; however, due to
there now being a second element with the same name,
use a more specific namespace for the element which
includes an identifier for the minor version.

This gives the following advantages: 
1. use of xsd:redefine allows extensions and perhaps restrictions
of the types without a change of namespace but with perhaps
(please correct me if I'm wrong) less ambiguity than with
xsd:substitutionGroups 
2. use of xsd:substitutionGroups and elements with changed
namespaces reflecting the minor version allows further use of
xsd:susbtitutionGroups by external customizers who use their
own namespaces for further extensions and perhaps restrictions

I've not tested this more than provisionally but it seemed to work
sufficiently, despite being a bit verbose.

There hasn't been a decision by UBL to use redefine for minor
versions and it might be that UBL 2 minor versions just redeclare
every element and type, making the above more academic for UBL
but maybe this is a worthy design pattern for general use with
all-global W3C XML Schema schema sets.

One for DW: how would this work with CAM?

All the best

Stephen Green



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