Lets say we have such a CGridView widget showing a list of users for administrator. Users have status „active“ or „disabled“.
Grid widget puts class „odd“ or „even“ to rows and we want to preserve this. So we want to add a class „disabled“ to rows with disabled users.
Let's say our table 'mug' has a column named 'color' of the type ENUM('red','green','blue').
We want to replace the textfield for the attribute color in the create and update forms of a 'mug' with a drop down list, which has the enum values as options.
The main code was contributed by zaccaria in the forum (see this post).
Relational databases do not support inheritance so if we need to represent it, we have to somehow store meta info while keeping performance by minimizing JOINs. One way to solve this problem is using single table inheritance. All fields for the whole class tree are stored in a single table. Class name is stored in the type field of the same table.
Yii makes it really easy for all to use their already made objects that automate everything we do. It provides also great power of flexibility and styling but hey, we programmers tend to complicate our lives and push a little more the power of our tools.