The system assigns each patient a patient ID number. In addition, the patient's name and date of birth are recorded. Some patients are resident patients (they spend at least one night in the hospital) and others are outpatients (they are treated and released). Resident patients are assigned to a room. Each room is identified by a room number. The system also stores the room type (private or semiprivate), and room fee. Over time, each room will have many patients that stay in it. Each resident patient will stay in only one room. Every room must have had a patient, and every resident patient must have a room.