I have read http://www.yiiframework.com/wiki/24/creating-a-dependent-dropdown/ (Dependen Dropdown Yii1), but I cant implementation in Yii2 because Yii2 not built-in AJAX functionality hem.. I am search about it and get this statement
Using CActiveRecord->updateAll() and CActiveRecord->deleteAll() with scopes and criteria requires some tricks that are explained in this article. While findAll() , find() and some other methods use scopes automatically, updateAll() and deleteAll() do not.
I found a standard Yii app's protected folder structure nearly perfect. With a few simple moves and a little bit change to the code, I managed to bring it to the level, which I found as fully perfect. I want to share my point of view, in case someone would like to use this structure as well.
You have that, when a product is on development they can change its API anytime. This change is quite important though, its related on how to set the events of your form, for example, the useful beforeSubmit.