RE: Alternatives to XML Schemas

["Bullard, Claude L (Len)" <clbullar@ingr.com>]

I have to differ just a little.  We are finding 
validation to be useful because even if we 
trust the source, we can't be sure the source 
wasn't subject to some error making process. 
I understand the notion of correct-by-construction 
but work on trust-but-verify.  The idea of 
the control is right but we have the problem 
that we don't want to write one process per 
source so we never have that amount of control 
a priori.  So we tradeoff efficiency for 
assurance.  In short, it depends a lot on 
the application and its role.  In the case of 
open message switch systems, the validation 
is of great importance.

Also note, that even where the schema is not 
applied for validation, its utility for specifying 
message/document types across an industry that 
is only now beginning to bid projects that span 
multiple products and multiple companies 
(the so-called contract-cited deliverable) is 
strong.   This kind of project is beginning to 
be pursued diligently in public safety (eg, 
APCO Project 36).   The period where we could 
bid wall-to-wall in all cases has passed.

The problem remains of ensuring the schema applied  
is the schema used for validaton.  One issue is spec'ing a 
transform that rewrites a schema dynamically 
because of small differences among trading partners. 

Len 
http://www.mp3.com/LenBullard

Ekam sat.h, Vipraah bahudhaa vadanti.
Daamyata. Datta. Dayadhvam.h


-----Original Message-----
From: Ronald Bourret [mailto:rpbourret@rpbourret.com]

One thing to remember about validation is that many applications won't
use it. If your document has a trusted source -- such as another
application that is under your control -- there is no need to validate.
You can assume that the document is constructed correctly and save the
time that would otherwise have been spent validating it. In other words,
validation is necessary only when you don't trust the source -- that is,
the document comes from a human or from a source you have no control
over.