Re: Global elements doing UBL a disservice

[Chin Chee-Kai <cheekai@softml.net>]

On Thu, 18 May 2006, G. Ken Holman wrote:

>>>H'mmm, ok, I'm starting to understand where you're coming from here.
>>>Educate me a bit here. Is UBL defined principally of global
>>>elements/types ?
>>
>>I think that's an orthogonal question, but yes UBL does follow the
>>"Garden of Eden" characterization of schema expression where all
>>elements and types are defined globally and there are no anonymous
>>types.  Other characterizations of schema design patterns are termed
>>"Russian Doll" (document element is global, all other local, all
>>types local), "Salami Slice" (all elements global, all types local)
>>and "Venetian Blind" (document element is global, all other local,
>>all types global).
>>
>>One of our many reasons to thank Eve Maler:
>>
>>  http://www.idealliance.org/papers/xml02/dx_xml02/papers/05-01-02/05-01-02.html
>>
>>I hope this helps.
>>
>>. . . . . . . . . . . . Ken

Thanks for a the nice URL link and Eve Maler's summary.  The article
exposes the various major modes of schema design methods and argues for
the Garden of Eden approach as adopted by UBL 1.0 (and also UBL 2.0?).
I was looking again at the global vs local issues when you bring up
this URL.  So it comes in just in time.

With all respects going to Eve's contribution and your (and probably
other UBL members') belief about why global (GoE) approach is better
over local, I am beginning to see evidence of such extreme approach
(of globalising everything) as doing a disservice to end-user reusing
UBL and its components.

To qualify my words, globally sharing of types is alright, but globally
sharing of elements is showing signs of problems.  If this is what's
called the Venetian Blind approach, then yes, I believe I'm beginning 
to see more advantages of VB than GoE.

Ref Eve's paper, the primary 3 points on why GoE is better than VB are
(1) mixture of element (namespace) qualifications,
(2) potential breakage of software
(3) accidental breakage due to elementFormDefault (again on software
    breakage)

I understand the concerns at that time may be different from the concerns
now, but I don't see how and why schema designs should be done in a way
that puts prevention of software breakage first (ie, easier for
programmers and software developers).  All things being equal, I'd agree
this could be considered, but there seems to be more at stake than
software breakage.  There may be other concerns that Eve hadn't put
in that article (to justify GoE over VB), so if there are further 
article updates, I'll be very glad if you can point them out to me 
as well.

Alright, I'm not here to start another religious debate on 
global vs local.  I only wish to point out that there're also
disadvantages inherent in the way UBL schemas are currently designed, 
and what's "best" then doesn't seem the same now.

In the next mail (when I get to it), I'll like to seek your help (again)
to check if the results and conclusions I got make some sort of sense.

Thanks.



Best Regards,
Chin Chee-Kai
SoftML
Tel: +65-6820-2979
Fax: +65-6820-2979
Email: cheekai@SoftML.Net
http://SoftML.Net/