is it required that every entity instance in the PRODUCT table be associated with an entity instance in the CD table? Why or why not?

Is it possible for a book to appear in the BOOK table without appearing in the PRODUCT table? Why or why not?

What are primary key characteristics considered desirable? Explain why each characteristic is considered desirable.

Under what circumstances are composite primary keys appropriate?

What is a surrogate primary key, and when would you use one?

When implementing a 1:1 relationship, where should you place the foreign key if one side is mandatory and one side is optional? Should the foreign key be mandatory or optional?

What are time-variant data, and how would you deal with such data from a database design point of view?

What is the most common design trap, and how does it occur?