1. Ray wants to start a DVD rental program at his stores that he plans to call Henry's DVD Club. He refers to each of his customers as "members." Each member in the club is assigned a number. He also stores the members' names and addresses. In addition, he stores the number of rentals the member has made and the date the member joined the club. He periodically has promotions during which members can earn bonus units that they can later apply to the cost of renting DVDs. He needs to store the number of bonus units the member has earned.

2. Modify in Exercise 1 so that it will also support the following situation. Ray wants to store information about the DVDs the club owns. When the club purchases a DVD, Ray assigns it a number. Along with the number, he stores the number of the movie on the DVD, the date the DVD was purchased, the number of times it has been rented, and the number of the member who is currently renting it. (If the DVD is not currently being rented, the member number will be null.) Ray also needs to store the number of the branch to which the DVD is assigned. Finally, Ray would like to store the history of the rental of each particular DVD. In particular, he needs to store the DVD number, the date of the rental, the date it was returned, and the number of the member who rented the DVD. Assume that a DVD could potentially be rented more than once on the same day. (Hint: Review the discussion of the categories of primary keys to determine what type of primary key would be appropriate for this relation.)