A simple and effective way to keep track what your users are doing within your application is to log their activities related to database modifications. You can log whenever a record was inserted, changed or deleted, and also when and by which user this was done. For a CActiveRecord Model you could use a behavior for this purpose. This way you will be able to add log functionality to ActiveRecords very easily.
Yii core messages refer to static text strings in the core Yii framework code which are meant to be displayed to end-users (e.g. core exception messages, default validation error messages). Customization of these core messages is needed in two circumstances:
The Definitive Guide introduces the fundamentals of managing URLs in a Yii application. In this tutorial, we introduce a practical technique that can quickly turn your application into using search-engine-friendly URLs.
First declare an attribute to store the file name in the model class (either a form model or an active record model).
Also declare a file validation rule for this attribute to ensure a file is uploaded with specific extension name.