Using the Shipper Drug Stores narrative, design and document a logical data model using Erwin. You should also make and document any reasonable assumptions where you feel the case is vague or ambiguous or missing any data necessary to meet the requirements.  However you cannot ignore or overrule the requirements that are explicitly stated.  Show all cardinality, prime keys and foreign keys. Use verbs to clarify your relationships. Show only the attributes that are contained explicitly in the case.

 Narrative

Shippers Drug Stores consists of a chain of retail stores across Canada. Each store has a unique store number. You will need to retain for each store its address and telephone #. Each store employs a number of pharmacists. The name and employee id for each pharmacist will be kept in the database. One pharmacist is the head pharmacist for the store. Employee ids are unique across the company. The company dispenses a wide range of pharmaceutical (drug) products. Each product has a description as well as a unique DIN (Drug Identifying Number) and is dispensed at a standard price for all stores. Some pharmaceutical products have adverse affects when taken in conjunction with other pharmaceutical products. These product combinations need to be defined. It is important to realize that any particular product can interact adversely with many other products and vice versa. Each store maintains its own physical inventory of these products and will need to know the current quantity it has on hand as well as the reorder level relevant for that particular store. Reorder levels may differ between stores. Customer information is stored only once centrally and shared by each store. It will include name, address email and phone #. Where a customer has signed up for online access a user name and password will also be retained. When initially presented by a customer, details for the medical prescription are entered as well by the store receiving and processing it. Prescriptions are assigned a unique id. The date written and the date presented need to be recorded as well as the prescribing physician. The name, phone and email are retained for each physician that has prescriptions on file. A prescription will be for only 1 product, and the total quantity dispensed for each product as well as the unit of measure needs to be maintained in the database. For simplicity assume that there are no repeats. All past dispensing activity for prescriptions is retained on file. When a prescription is dispensed (filled), the pharmacist dispensing that prescription will be recorded for that prescription as well as the date that it was dispensed.