Create Rule To Validate 2 Fields In Cactiveform

If my model User have only one attribute name, it is easy for me to add the rule unique to it so it avoids the situation that someone input user’s name which is already in the database. But now I change from name to first name and last name. So I would like to make a new rule for both 2 attributes that the system will search in the database and return that either that name exist or not.

I would highly appreciate any suggestions :).

Unique attributes validator.

Problems solved, thank your help Keith :)