Administering RBAC in PHP 5 CMS Framework
November 17, 2008[From WebReference]
The administration of the system could be done by writing directly to the database, since that is what most of the operations involve. There are strong reasons not to do so. Although the operations are simple, it is vital that they be handled correctly. It is generally a poor principle to allow access to the mechanisms of a system rather than providing an interface through class methods. The latter approach ideally allows the creation of a robust interface that changes relatively infrequently, while details of implementation can be modified without affecting the rest of the system.
The article continues at http://www.webreference.com/programming/php_5_cms_framework_development2/