What is a database index? When would you use one? What's the downside of using an index?

What's the difference between a primary key and a unique key? What's a foreign key? What's a composite key?

When should you consider denormalizing data? What are the advantages of doing this? What are the disadvantages?

What is an artificial (derived) primary key? When should it be used? How would you compare this to using a natural primary key?

Explain how you would implement the following database relationships when designing tables:

• one to one
• one to many
• many to many