There are three main entities in our model. There is Ambulance Patients entity which represents all patients coming to the hospital by ambulance cars. The second entity indicates to all patients entering the emergency room without the ambulance cars, and we gave it WalkIn Patients as an entity name. This entity was classified into two entities: WalkIn High and WalkIn Low. The third entity is called Search entity and it searches the exceptional patients in the Urgent Doctor queue.
We have assigned only one variable indicating to the number of patients residing in both doctors' queues and the front-desk queue.