Instructions: Based on the description below, please draw an ER diagram using the notation style used in class. Indicate both maximum and minimum cardinality. Clearly state any reasonable assumptions you have made drawing the diagram.

Project Description

After completing a course in information systems management, you have been hired as a summer intern by Mountain View Community Hospital. Your first assignment is to develop a high-level E-R diagram for the hospital. You conduct interviews with a number of hospital administrators and staff to identify the key entities for the hospital. After a short time, your team has identified the following entities:



Ward - a treatment center within the hospital. exs of wards are maternity and emergency care. Each ward has a ward number (identifier) and a ward name.
Patient - a person who is either admitted to the hospital or is registered in an outpatient program. Each patient has a patient number (identifier) and name.
Physician - a member of the hospital medical staff who may admit patients to the hospital and who may administer medical treatments. Each physician has a physician ID (identifier) and name.
Bed - a hospital bed that may be assigned to a patient who is admitted to the hospital. Each bed has a bed number (identifier), a room number, and a ward number.
Item - any medical or surgical item that may be used in treating a patient. Each item has an item number (identifier), description, and unit cost.
Employee - any person employed as part of the hospital staff. Each employee has an employee number and name.
Treatment - any test or procedure performed by a physician on behalf of a patient. Each treatment has a treatment ID that consists of two parts: treatment number, and treatment name.


The team next recorded the following information concerning relationships:



Each hospital employee is assigned to work in one or more wards. Each ward has at least one employee, and may have any number of employees. The hospital records the number of hours per week that a given employee works in a particular ward.
Each ward has exactly one employee who is designated nurse in charge for that ward.
A given patient may or may not be assigned to a bed (since some patients are outpatients). A bed may or may not be assigned to a patient.
A patient must be referred to the hospital by exactly one physician. A physician may refer any number of patients, or may not refer any patients.
Physicians may perform any number of treatments on behalf of any number of patients, or may not perform any treatments. A patient may have treatments performed by any number of physicians. For each treatment performed on behalf of a given patient by a particular physician, the hospital records the following information: treatment date, treatment time, and results.
A patient may optionally consume any number of items. A given item may be consumed by one or more patients, or may not be consumed. For each item consumed by a patient, the hospital records the following: date, time, quantity, and total cost (which can be computed by multiplying quantity times unit cost)