Suppose that you are required to implement a system for a car dealership.
The system needs to store information about each customer.
This includes the customer's ID number, name, address and contact number. The dealership sells both used and new cars. For all cars the registration number, year, make cost price and selling price must be stored. The dealership sells both new and used cars. Information regarding the previous owner, i.e. the contact person's name and number, must also be stored for each used vehicle.
The selling price of a car is calculated to the cost price plus a percentage markup of the cost price, i.e. selling price = cost price + cost price x markup percent.