As written on the API docs: An Action Provider Widget is a widget that has declared several actions by using its 'public static function actions()'. After, a Controller can easily import all its declared actions on its 'public function actions()'.
If you have to display a overview of related data in a table,
you can use the CListView, create your view with table/tr/td tags
and implement db-queries in the view to display detaildata of the current (master-)record.
Trying to learn and help some other programmers to find their solutions on the Yii Forum (I think is a superb way to learn the framework), I was facing one challenge with an external library that a fellow programmer wanted to use -quite good indeed: PHPExcel. And what is PHPExcel?