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RE: Alternatives to XML Schemas
- From: "Bullard, Claude L (Len)" <email@example.com>
- To: Ronald Bourret <firstname.lastname@example.org>, email@example.com
- Date: Wed, 07 Mar 2001 12:28:23 -0600
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.
Ekam sat.h, Vipraah bahudhaa vadanti.
Daamyata. Datta. Dayadhvam.h
From: Ronald Bourret [mailto:firstname.lastname@example.org]
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