What are MySQL foreign keys?

Question

In an answer on Stack Overflow, I saw this code:

CREATE TABLE Favorites (
    user_id INT NOT NULL,
    movie_id INT NOT NULL,
    PRIMARY KEY (user_id, movie_id         


        

Answer 1

You can also add the ability to cascade when a related record is deleted. For example if I have a library table with many books in a related "book" table and I delete a given library from my library table its' dependent book records will also be deleted.