Defining Roles in asp.net using oracle

[Ravindra]

Hi,
I am Ravindra,currently doing a project in asp.net(with oracle as database).
Our team has assigned me to define roles for our webproject
using oracle as a database.
As I am new to asp.net,not able to find correct way to define roles in
web.config of our application.
So,If anybody know the links or any data related to this please help
me.
thanks in advance