Re: What databases have taught me

> It's called "The Single Resonsibility Principle" (SRP). This
> principle says that a software module should have one, and only one
> reason to change. For example, a module that contains business rules
> should not also contain report formatting. Business rules and report
> formatting change for completely different reasons, and should
> therefore be isolated in completely different modules.

Ok, lets say we want to add a module formatting the report and one module doing the "business logic". The formatting module should only change if you need to change the format, right? The business module should only change if you need to change the business logic, right?

Now we want to add a new atttribute, telephoneno. This new attribute should also be printed in the report. Doesn't this change in business logic also force the format module to change? The format module may change by other reasons than formatting reasons.

Fredrik Bertilsson
http://frebe.php0h.com Received on Thu Jun 29 2006 - 06:45:52 CEST