• From: bryan rasmussen <rasmussen.bryan@g...>
• To: Michael Kay <mike@s...>
• Date: Tue, 7 Jul 2009 15:30:06 +0200

hmm, after sending off my last message I noticed - as is generally the
case - that Michael Kay already touched on the issue..

on the types of validation..
> (a) laws of nature - children have two parents, planes take off before they
> land
>
> (b) rules decided by the business (or more generally, by the user community)
> - every customer belongs to one branch office, every employee is over 16,
> ISBNs are ten digits long
>
I would split the (b) into (b) rules decided by the community
exchanging the data -
 ISBNs are ten digits long, contracts must be signed, currency must be
in a recognized format..These and (a) are the actual validity rules,
the rules that allow exchange of documents defined as valid by a group
of those doing the exchanging..

and

(c) rules decided by the business for their processing of valid
documents - workflow related - actual category of 'business rules'
that is to say something can fail these but still be 'valid':
payment due in more than 2 months, payment greater than this amount
needs two signatures, every customer belongs to one branch office.

> (c) rules decided by IT system designers - every customer has at most three
> phone numbers, tables cannot be nested within tables, messages are limited
> to 140 characters
>
And this would be
(d)  the workflow to allow data that is valid to be processed to be
placed within various IT systems - generally automated.

I would say that any workflow that can be automated and is of type d
is not a business rule though...

rest of the message was better phrased than what I could do of course.

Cheers,
Bryan Rasmussen