The program I am developing is going to be used by several group users with different level permission. Some of them are not allowed to access some functions(through menu and buttons) and only permitted to retrieve data related to that person from database. I have developed all-in-one program but now I am facing difficulty to customize the interface and functions for each user based on their login username.
My program is in VB6/NT/SQL7 environment and for 30+ users. I am looking for an efficient way to do it.
My question can be further divided into two parts.
1) in a form with menu and buttons. How to disable some of these buttons based on username? Where to store user group information(SQL7 or a text file)?
2)For SQL database, How to setup security to
allow only user-related information being retrieved from a single table ?(An alternative way may be just to set up restriction to the query in vb code?)

I would like to hear your experience and suggestions. Thank you.