Why use an auto-incrementing primary key when other unique fields exist?

Question

I\'m taking a course called \"database systems\" and for our class project I have to design a website.

Here\'s an example of a table I created:

CREATE TA         


        

Answer 1

I go with all the answers above. I would say an ID is easy to implement and when it comes to indexing, Int is always preferred compared to a varchar. Your professor should know better, why would he say no to Int id is above me!