Relationship with a table without unique/primary key
Primary keys (and foreign keys) should be unique, otherwise how does the database know which row the foreign key relationship is pointing to?


  I'm thinking about using a primary key int, but what if one day i go in overflow? Suppose i got so much works to store that i go out the limit?


I wouldn't worry about hitting the limit for ints. The mysql documentation lists the limits of various int types. If you're concerned about having more than 2 billion rows anytime soon, you can always use bigint and have over 9 quintillion rows before overflowing. 18 quintillion if you used unsigned.