Session of role

Question

i have 2 web pages one for login and other index.
for login 3 cols are defined in database table. name, password, and role
i want that when user loges in a session is created that saves the role of user(means it takes the role from database table for that particular user). after loging in to the index pages the role session is to be checked whether the user is user or admin. how is it possible. please help me.