I have a users table for registered users. These registered users can add contacts that have registered (Registered users) and also contacts that have not registered (That can register in future).
What is the best database structure?
I manage a website since 6 years and I have all the users in the same table with a column named "profile", with any problem at all. Is very useful to have all in the same table. You could have a boolean column: registered and non registered.