Reference no: EM132116098

Question 1 : A company database needs to store information about employees (identified by ssn, with salary and phone as attributes), departments (identified by dno, with dname and budget as attributes), and children of employees (with name and age as attributes).

Employees work in departments; each department is managed by an employee; a child must be identified uniquely by name when the parent (who is an employee; assume that only one parent works for the company) is known. We are not interested in information about a child once the parent leaves the company.

Draw an ER diagram that captures this information.

Question 2 : 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 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.

Draw an ER diagram that captures the preceding information. Identify any constraints not captured by the ER diagram.