php open source web application for learning

Question

Is there a good PHP open source web application from what we can learn? Learning mainly includes:

1. Considering and taking care of ACID properties
2. Building Data Access Layer
3. Error handling and reporting to user

I have considered WordPress, but since it uses MyISAM tables, they are not taking care of ACID.

Answer 1

Perhaps the applications based on the Zend Framework like Magento, Digitalus CMS, etc

Link : 5 opensource application built around Zend framewok.