A Campus Magazine Subscription Agency (CMSA) distributes order forms offering reduced prices on magazine subscriptions for students at universities and colleges. CMSA have both paper-based magazines and online magazines. CMSA records magazine data including name, description, number of issues per year, and subscription price. In addition, CMSA maintains data about whether a paper-based magazine is printed on recycled paper and whether an online magazine requires the Flash plugin. If a subscription is more than 24 months, CMSA takes 20% off the regular subscription price.

Order forms are distributed at different campuses by local representatives. The reps are given sets of order forms with two codes (one to indicate the sales representative, and one unique to each form). A set of forms is placed in a different location (e.g., science building in campus). The rep informs the agency where each set of forms has been placed. When reps change, new forms are issued. But previous reps still receive commissions for any orders that come in on their forms. Each campus has only one rep.

When CMSA receives a subscription order form, all the customer data must be recorded (including name, university affiliation, address, and phone numbers). A customer can subscribe to more than one magazines. They can also renew an existing subscription. According to the codes on each form, CMSA knows who is entitled to the commission. In addition, CMSA provide reports back to the representatives showing which locations resulted in the most sales. If some locations are not working well, new locations can be tried. The system also includes some basic demographic data about each campus, including number of students, and whether it is a community college or university. This allows them to produce reports comparing sales per 1000 students across different types of campuses.

Required assumptions: Write down your assumptions about the following (and make sure your ERD is consistent with the assumptions):

1. Can a magazine have both paper and online editions?
2. Are all sales representatives paid at the same commission rate?
3. Do all order forms get recorded in your system, or only those on which an order was placed?
4. Are all subscriptions placed on the same order form for the same duration (i.e., do they all have the same start date and end date)?