Use Case Diagram: Actors: Customer AppointmentSetter Technician PartsDepartment Use Cases: Schedule Appointment (Customer): Customer interacts with the system to schedule an appointment. Set Appointment (AppointmentSetter): AppointmentSetter sets appointments based on customer requests. View Schedule (Technician): Technician views their schedule to see assigned appointments. Order Parts (PartsDepartment): PartsDepartment orders necessary parts for appointments. Relationships: Schedule Appointment <-> Set Appointment: The customer schedules an appointment, and the setter sets the appointment. Set Appointment <-> View Schedule: The setter sets appointments, and technicians view their schedules. Set Appointment <-> Order Parts: Parts needed for appointments are ordered by the PartsDepartment. View Schedule <-> Order Parts: Technicians might need to check parts availability when viewing their schedules