Please review lecture slides carefully before you start to work on your assignment. Consider the following requirements for a HEALTHCARE database. Draw an ER diagram. You need to specify (1) key attributes of each entity type, (2) cardinality ratio, and (3) participation constraint on each relationship type. Please provide your assumptions if needed.

Patients are identified by an SSN, and their names, addresses, and ages must be recorded. Doctors are identified by an SSN. For each doctor, the name, specialty, and years of experience must be recorded.

Each pharmaceutical company is identified by name and has a phone number.

For each drug, the trade name and formula must be recorded. Each drug is made by a given pharmaceutical company, and the trade name identifies a drug uniquely from among the products of that company. If a pharmaceutical company is deleted, you need not keep track of its products any longer.

Each pharmacy has a name, address, and phone number.

Every patient can visit more than one doctor. Every doctor has at least one patient.

Each pharmacy sells several drugs and has a price for each. A drug could be sold at several pharmacies, and the price could vary from one pharmacy to another.

Doctors prescribe drugs for patients. A doctor could prescribe one or more drugs for several patients, and a patient could obtain prescriptions from several doctors.

Each prescription has a date and a quantity associated with it.

Pharmaceutical companies have contracts with pharmacies. A pharmaceutical company can contract with several pharmacies, and a pharmacy can contract with several pharmaceutical companies. For each contract, you have to store a start date, an end date, and the text of the contract. Pharmacies appoint a supervisor for each contract. There must always be a supervisor for each contract, but the contract supervisor can change over the lifetime of the contract.