Create an ER Diagram for a patient appointment system as the following: The doctor can be scheduled for many appointments, but may not have any scheduled at all. The doctor identified by his employee number and he has first name and last name. Each appointment is scheduled with exactly 1 doctor. Each appointment has unique appointment number A patient can schedule 1 or more appointments. Each patient has patient id number, first name, last name, date of birth and address. One appointment is scheduled with exactly 1 patient. An appointment must generate exactly 1 bill, a bill is generated by only 1 appointment. One payment is applied to exactly 1 bill, and 1 bill can be paid off over time by several payments. A bill can be outstanding, having nothing yet paid on it at all. One patient can make many payments, but a single payment is made by only 1 patient. Some patients are insured by an insurance company. If they are insured, they can only carry insurance with one company. An insurance company can have many patients carry their policies. For patients that carry insurance, the insurance company will make payments, each single payment is made by exactly 1 insurance company. Identify the participating entity types, and the attributes of each entity type including the primary key, the relationship classification, the cardinality ratio, and relationship participation. Make any assumption you need