Difference between one-to-one and one-to-many relationship in database

Question

This is probably a basic(dumb) question but when having a one-to-one relationship in a database the other table has a foreign key ID(in this example). And in a one-to-many relat

Answer 1

Similarly by example, a product has only one product code, so it's one-to-one relationship (product <-> ABC123), but a customer can purchase more than one product, so it's one-to-many relationship (person <->>>product).