Title: Re: [ubl] Discussion of substitution groups
That would break UBL NDR rules of
course.
I think we'd need to start a whole new
discussion in UBL on this and that
would
probably take more time than we have.
I remember we discussed it in Hong
Kong
and decided we need the minor version
namespace changes.
I have seen the problems you get when
the minor versions don't have
namespace
changes and they are highly regretable.
I'd
hate to think of not learning at all from
history.
Then of course there is the option that
we
don't have minor versions and that
seems
a catastrophic departure from all UBL
has
achieved so far (IMO).
Steve
----- Original Message -----
From:
CRAWFORD, Mark
To:
;
Sent: Tuesday, July 19, 2005 10:47
AM
Subject: Re: [ubl] Discussion of
substitution groups
And if we don't minor version our namespaces?
Mark R.
Crawford
Senior Research Fellow - LMI XML Lead
W3C Advisory Committee
and OASIS Representative,
Vice Chair - OASIS UBL TC
Vice Chair -
UN/CEFACT Applied Technologies Group
Chair - UN/CEFACT XML Syntax Working
Group
Co-Chair ISO TC154 Subcommittee for ISO 15000-5
--
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McLean, VA
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-----Original Message-----
From: Stephen
Green <>
To: CRAWFORD, Mark
<>;
<>
Sent: Tue Jul 19 04:11:01 2005
Subject:
Re: [ubl] Discussion of substitution groups
I believe we need to use
substitution groups for minor
versioning as per NDR Rules VER 8 and VER 9,
to
allow use of imports of previous versions' schemas and
xsd
derivation. I believe this has been an important part
of the NDR design
from the beginning of UBL, it having
been intended since then that minor
releases and
customisations would use XSD-enabled inheritance
and
polymorphism. The reason the above requires substitution
groups to
make it work in UBL is the highly structured, type
oriented and essentially
complex nature of UBL. I believe
it would be impossible or at best far more
difficult to
achieve the same aims with a local schema design, This,
I
believe, was the main reason for the use of the global
element and global
type design. I also now believe it
would be impossible or very difficult to
achieve the same
goal using XSD redefine (or any other XSD method
for
that matter). (IMO) the only choice might be whether to use
abstract
elements and types, forcing substitution and I
see nothing to be gained and
much possible confusion from
this so I personally would rather avoid it, as
we did with
the design we recommended to the TC from the UBL
minor
versioning [ver] working group in April. Thankfully, Marty
has
well demostrated that a working design for substitution
group use without
abstracts can be used for codelist extension
too.
Overall, in just a
few words, we need it for XML with
XSD to be properly eXtensible in
UBL.
All the best
Steve
----- Original Message
-----
From: "CRAWFORD, Mark" <>
To: "Stephen
Green"
<>;
<>
Sent:
Monday, July 18, 2005 4:08 PM
Subject: RE: [ubl] Discussion of substitution
groups
> This all the more persuades me that for
>
minor versioning and codelists we have
> only one sensible option -
substitution
> groups (without use of abstracts).
But if our
schema follow our NDRs and are created from models as
expressed in the
spreadsheets, why do we need to use substitution groups
at
all?
