ER-Diagram and EER-Diagram
Holiday Travel Vehicles (HTV) sells new recreational vehicles and travel trailers. When new vehicles arrive at the HTV, a new vehicle record is created. Included in the new vehicle record are vin-number, model, year, manufacturer, and base cost. Several manufacturers that supply the vehicle are Toyota, Chrysler and Ford. When a customer arrives at HTV, he or she works with a salesperson to negotiate a vehicle purchase. When a purchase has been agreed upon, a sales invoice is completed by the salesperson. The invoice summarizes the purchase with invoice no, date, vehicle vin-number, sale tax and final price. Customers are assigned a customer ID when they make their first purchase from HTV. Name, sex, DOB, address (street, city, zipcode), and phone number are recorded for the customer. Each invoice lists just one customer. A person does not become a customer until he or she purchases a vehicle. Overtime, a customer may purchase a number of vehicles from HTV. Every invoice must be filled by only one salesperson. A new salesperson may not have sold any vehicles, but an experienced salesperson has probably sold many vehicles. The first time when the staff joins the company, they are given staff ID. Other information such as name, address (street, city, zipcode), sex, DOB, phone no and position will also be captured by the system. Staff are assigned position such as clerk, salesperson or manager. There are two types of staff, either full-time or part-time. Full-time staff is given monthly salary and bonus while part-time staff work on hourly basis and overtime.
Based on the information given about the above company, create a single integrated Entity Relationship Diagram or EER-Diagram using the class notation diagram from UML. In your diagram, you should identify all the entities, attributes, primary key, relationship, and multiplicity constraints.