News Feed
Sections




News Archive
Looking for more information on how to do PHP the right way? Check out PHP: The Right Way

Mathias Verraes:
DRY is about Knowledge
August 04, 2014 @ 10:51:50

In this new post to his site Mathias Verraes approaches the concept of the DRY principle (Don't Repeat Yourself) as being more about knowledge. He includes two "real world" examples where the business rules can change around you.

"Don't Repeat Yourself" was never about code. It's about knowledge. It's about cohesion. If two pieces of code represent the exact same knowledge, they will always change together. Having to change them both is risky: you might forget one of them. On the other hand, if two identical pieces of code represent different knowledge, they will change independently. De-duplicating them introduces risk, because changing the knowledge for one object, might accidentally change it for the other object.

In his examples, he shows how hard-coded rules (like "a product container can only contain 3 products") could just be around certain needs, not the entire range of requests. He covers some of the principles of Domain-Driven Design and how they apply here, pointing out that changing rules in one part of the application can have an effect on other parts depending on it.

0 comments voice your opinion now!
dry dontrepeatyourself principle knowledge domaindriven design business goal

Link: http://verraes.net/2014/08/dry-is-about-knowledge/

blog comments powered by Disqus

Similar Posts

Tobias Schlitt's Blog: Reading recommendation: PHP Design Patterns

DevShed: Handling File Data with the Facade Pattern in PHP 5

Stefan Mischook's Blog: Why PHP is the choice language - a business owners perspective

Federico Cargnelutti's Blog: Domain-Driven Design with Zend Framework

Stuart Herbert's Blog: Missing: The Business Case For PHP


Community Events





Don't see your event here?
Let us know!


release framework interview podcast series introduction symfony tips library bugfix community zendserver language list conference api developer laravel deployment voicesoftheelephpant

All content copyright, 2014 PHPDeveloper.org :: info@phpdeveloper.org - Powered by the Solar PHP Framework