RE: [ubl-dev] SBS and Restricted Data Types

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

At 2006-05-04 11:31 -0400, Chiusano Joseph wrote:
>The same would apply for data type restrictions - if there were
>some overriding, unavoidable reason that a trading partner could not
>honor a length for a description of (say) 30 characters, and they
>instead sent you 100, then there needs to be requirements for handling
>this situation (e.g. is it ok to truncate the characters beyond the
>30th?).

Then put that in a business rule (i.e. asserted using Schematron), 
don't change the constraints of the expression of the information in 
the document vocabulary.

>What has happened to the notion of contract-based interoperabilty, where
>trading partners adhered to a technical contract to the greatest degree
>feasible and possible? Why leave data type restrictions (such as string
>length) out in the cold? I really don't understand what the issue is
>here (please note that that is not a criticism of your perspective).
>
>So with all due respect, and for what it may be worth, I completely
>differ with your views on interoperability as expressed below. That is
>not to say in any way that they are incorrect - I just have a very
>different perspective on interoperability, and the possibilities that
>can be realized.
>
>Please correct my thinking if needed - I want to be told I am wrong if
>you or anyone else believes I am.

Who is to say what is "correct" Joe when dealing with perspectives?

For my two cents (Canadian), implementation constraints such as 
string length have no role in XML vocabularies.  XML vocabularies are 
used to express user's information so that users can convey what they 
need to do their business.

If an implementation chooses to constrain a user's use of a 
vocabulary, that is up to the implementation, not to the abstract 
definitions expressed in the vocabulary.

Implementations of standards differentiate themselves by how well 
they work with the standards and which features they offer to their 
users.  If in my business I absolutely need to use 100 characters for 
my description, then I'm going to go out there looking for an 
implementation that supports me.  If I can't find one, then I'll have 
other decisions to make, but I would have had that if the "standard" 
arbitrarily restricted me.  But I don't have to make those decisions 
if there are applications that support me.

I don't think implementations should arbitrarily constrain users of 
XML vocabularies ... that is the tail wagging the dog.

If I enter into a trading agreement with a trading partner and we 
mutually agree that our use of UBL will require that a given string 
be constrained to 30 characters, that is a business/technical 
decision between me and my partner, it is not a constraint on the 
document vocabulary, and I'll express that constraint as an assertion 
that can be tested after structural integrity has been tested.

. . . . . . . . . . . . . Ken

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