Group3
The Prescriptions-R-X chain of pharmacies has offered to give you a free lifetime supply of
medicine if you design its database. Given the rising cost of health care, you agree. Here’s the
information that you gather:
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
sold 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 has a primary physician. 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. You can
assume that, if a doctor prescribes the same drug for the same patient more
than once, only the last such prescription needs to be stored.
Pharmaceutical companies have long-term contracts with pharmacies. A phar-
maceutical 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
super- visor for each contract, but the contract supervisor can change over the
lifetime of the contract.
1. Draw an ER diagram that captures the preceding information. Identify any con-
straints not captured by the ER diagram.
2. How would your design change if each drug must be sold at a fixed price by all
pharmacies?
How would your design change if the design requirements change as follows: If a doctor prescribes the same
drug for the same patient more than once, several such prescriptions may have to be stored.
