Re: OOP/OOD Philosophy

On 2 Jul 2005 10:55:05 -0700, "topmind" <topmind@xxxxxxxxxxxxxxxx>
wrote:

>In my domain one often cannot know ahead of time what will change.

It's not so much a matter of knowing what will change, or even how it
will change. It's a matter of recognizing that certain things will
change at a different rate than others. For example report formats
are will change at a different rate than business rules. GUI layout
will change at a different rate than database schemae.

You don't even have to know whether one will change more frequently
than the other. You just have to be able to make a reasoned guess
that they will change at different rates and for different reasons.

We try not to couple report formats to business rules because it would
be a shame to inadvertently break the business rules by moving a
column on a report. We try to decouple the GUI layout from the
database schemae because it would be a shame to crash the GUI when
adding a new column to the database.



-----
Robert C. Martin (Uncle Bob) | email: unclebob@xxxxxxxxxxxxxxxx
Object Mentor Inc. | blog: www.butunclebob.com
The Agile Transition Experts | web: www.objectmentor.com
800-338-6716


"The aim of science is not to open the door to infinite wisdom,
but to set a limit to infinite error."
-- Bertolt Brecht, Life of Galileo
.

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