Question

Draw ER Diagrams for the following narratives.

Draw ER Diagrams for the following narratives. The Human League Surgery has doctors, nurses, midwives and patients. The patient has to telephone for appointments with the doctors or nurses and these appointments are allocated by the receptionist. An appointment can only be made with one doctor, midwife or nurse at a time. A patient may also only be registered with one doctor. 1. "Authors are responsible for writing plays that are performed in theatres. Every time a play is performed, the author will be paid a royalty (a sum of money for each performance). Plays are performed in a number of theatres; each theatre has maximum auditorium size, and many people attend each performance of a play. Many of the theatres have afternoon and evening performances. Actors are booked to perform roles in the plays; agents make these bookings and take a percentage of the fee paid to the actor as commission. The roles in the plays can be classified as leading or minor roles, speaking or non-speaking, and male or 2. female." "A database will be made to store information about patients in a hospital. On arrival, each patient's personal details (name, address, and telephone number) are recorded where possible, and they are given an admission number. They are then assigned to a particular ward (Accident and Emergency, Cardiology, Oncology, etc.). In each ward there are a number of doctors and nurses. A patient will be treated by one doctor and several nurses over the course of their stay, and each doctor and nurse may be involved with several patients at any given time." 3.

Answer 1

1) An ER diagram for the first narration is below :-

Address Salary Name Gender Emp ID Employee Contact Designation Assien Appointment IS A Midwives Receptionist Nurses Doctors Assign Assign Patients Call Contact Sickness Patient ID Address Gender Name

Explanation - All the attributes like name of the patient, address and etc of the entities are shown in ellipse shape and entities like patients, nurses, doctorsetc are shown in rectangle shapes . The diamond shape like assign or callis used to show the action happening between the two entities . The relationships between the entities are shown by using one single I for one and only one bar or double bar II for many .

2) An ER diagram for the second narration is below :-

Agents Address Gender Royalty Contact Book Play Author Commission Actors Name 1 Perform M Plays Write M Performed Royalty Pa M 1 People Performance Theatres Max audi size Evening Afternoon Male Leading Has minor Speaking Classification Roles Non-Speaking Female

Explanation - All the attributes like name of the author , address and etc of the entities are shown in ellipse shape and entities like plays , author , roles etc are shown in rectangle shapes . The diamond shape like HAS or paid is used to show the action happening between the two entities . The relationships between the entities are shown by using 1 or M where 1 denotes one and only one and M denotes many .

3) An ER diagram for the third narration is below :-

Admission Number Contact Address Patient Name 1 Accident 1 Emergency Ward tvpe Ward Cardiology Ward Number 1 Oncology HAS M 1 Doctors Nurses M 1 1

Explanation :- In the ER diagram above , the relationship between the patients and doctors , nurses is a shown as one patient can be treated by only one doctor and many nurses but one doctor and one nurse can treat many patients . All the attributes of the entities are shown in ellipse shape and entities are shown in rectangle shapes . The diamond shape is used to show the action happening between the two entities .