Joe's Pharmacy
A customer comes in with a prescription to be filled. The prescription contains the
date, the patient's name, the physician's name and ID number, the drug name, dose,
and quantity to be dispensed. The pharmacy assigns a prescription number. The
pharmacist checks to see whether there is a record on hand for that customer, and if
not a new record is created with the customer’s name, address, phone number, date of
birth and any known drug allergies. If there is a record the pharmacist checks to see
whether the new medication is contraindicated based on the information in the
customer's record. If not the pharmacist then fills the prescription, provides it to the
customer, and updates the customer’s record.
Some simplifications: Assume that there is only one pharmacist (Joe.) Assume that a
separate prescription is written for each separate drug to be dispensed. Assume that
when we are talking about a drug allergy that each allergy involves only one drug (i.e.
we are not looking at drug interactions.)
ERD Cases -- Draw an ERD for Each
1) Bankrupt airlines offers numerous flights between destinations in the western US
every day. Bankrupt is famous for their "one price -- one class" policy. Information
maintained about flights includes flight number, departure time, departure time,
departure city (the specific airport), arrival time, arrival city (the specific airport), and
days flown (e.g. M, W, F) For each specific date that a flight will be run there is a
record of the date and the number of seats on the aircraft as well as the price. To
reserve a seat on one of Bankrupt airlines flights a customer provides his or her name,
address, and a telephone contact number. A ticket states the ticket number, departure
date, ticket conditions and fare. Although each flight can be booked by many
customers and each customer can book many flights Bankrupt airlines policies require
that each customer must have a ticket to board each flight and that each ticket must be
issued to only one passenger.
2) The TRY yogurt company makes and sells many products. Each product is
composed of several raw ingredients that are supplied by various vendors. A
particular ingredient is always supplied by the same vendor; however a vendor may
supply more than one ingredient. The product line is divided up so that only one
department is responsible for making a particular product. However each department
is responsible for more than one product. The following data fields must be stored in
the TRY yogurt Company's database; product number, product name, ingredient
number, ingredient name, quantity of the ingredient required for each product, vendor
ID, vendor name, vendor address. Department ID code, department name, department
office address, department phone number.