Rbac - How To Check/change Role Of Users

Hey there,

I just started using yii in my first little project. Yesterday I started experimenting with the RBAC-System of yii. I know there are Extensions for that but I want to understand it myself so I decided to use yii only.

I only created 2 roles "User" and "Admin" and assigned them to 2 Users

$auth->createRole('admin','Administrator');
$auth->createRole('user','Benutzer');

$auth->assign('admin',4);
$auth->assign('user',5);

In my Controller I created the following accessrules to see if it works

return array(
            array('allow',
            	'actions' => array('index', 'add'),
            	'roles' => array('admin'),
            ),
            array('deny',
            	'actions' => array(),
            	'users'=>array('*'),
        	),
        );

It works. My Admin can access both actions and my normal User cannot. BUT, how can I see the actual role I assigned to the User? Or how can I get all Users or all Admins at once?

I'm planning to write an Admin Panel where I can change the userroles but I don't know how I can get the actual role a user has.
I know I could save the role in my user Table in an additional column but this could lead to inconsitency of my DB. And the roles are already stored somwhere so I should be able to access this information

Any suggestions?