1. Dept. of Computer & Information Sciences
Riyadh Philanthropic Society For Science
Prince Sultan College For Woman
Dept. of Computer & Information Sciences
CS 340
Introduction to Database Systems
(Chapter 4 Tutorial)

2. Exercise 1
A rental car agency classifies the vehicles it rents into four categories:
compact, mid-size, full-size, and sport utility. The agency wants to
record the following data for all vehicles: Vehicle-ID, Year, and
Color. There are no unique attributes for any of the four classes of
vehicle. The entity type vehicle has a relationship with a customer
entity type. None of the four vehicle classes has a unique relationship
with an entity type. Would you consider creating a class/subclass
relationship? Why or why not?
Chapter 4 Tutorial 1

3. Exercise 1 (Solution) No, because:
There are no unique attributes for any of the four classes of
vehicle.
None of the four vehicle classes has a unique relationship
with an entity type.

4. Exercise 2
Identify the entities and relationships for the following description
and draw an EER diagram.
A company leases various types of vehicles, identified by a VID and
having a gross vehicle weight (GVW). Trucks have a load capacity
and a length. Cars have a seating capacity. Individuals (known by
their name and drivers license) can lease one of the company’s
vehicles for a specific period of time.
Chapter 4 Tutorial 2

5. Exercise 2 (Solution) License No LeasePeriod VID M LEASES N PERSON
VEHICLE
GVW
Name d
TRUCK
CAR
Load
Length
SeatingCapacity
Chapter 4 Tutorial 3

6. Exercise 3
Identify the entities and relationships for the following description
and draw an EER diagram.
Library staff, each having an ID, name, and title work on a number of
projects, each with its own name, start date and end date. Any given
project is only worked on by one staff member. Every staff member has a manager (except for the director).
Chapter 4 Tutorial 4

7. Exercise 3 (Solution) ID Name ProjectName 1 N STAFF PROJECT StartDate
WORKS-ON N
STAFF
PROJECT
StartDate
Title
EndDate d
MANAGER
STAFF_MEMBER
DIRECTOR 1 N
MANAGES
Chapter 4 Tutorial 5