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

Let's assume you have a table with two attributes A and B. If A is a candidate key and B is not then the relationship between A and B is 1 to many. If both A and B are candidate keys then the relationship is 1 to 1.