1. Introduction to Database Systems
Riyadh Philanthropic Society For Science
Prince Sultan College For Woman
Dept. of Computer & Information Sciences
CS 340
Introduction to Database Systems
(Chapter 3 Practice Exercises)

2. Exercise 6
Consider the following information about a university database:
• Professors have a SSN, a name, an age, a rank, and a research
specialty.
• Projects have a project number, a sponsor name (e.g. NFS), a
starting date, an ending date, and a budget.
• Graduate students have a SSN, a name, an age, and a degree
program (e.g., M.S. or Ph.D.).
• Each project is managed by one professor (known as the project's
principal investigator).
• Each project is worked on by one or more professors (known as the
project's co-investigators).
• Professors can manage and/or work on multiple projects.
Chapter 3 Practice Exercises 16

3. Exercise 6
• Each project is worked on by one or more graduate students (known
as the project's research assistants).
• When graduate students work on a project, a professor must
supervise their work on the project. Graduate students can work on
multiple projects, in which case they will have a (potentially
different) supervisor for each one.
• Departments have a department number, a department name, and a
main office.
• Departments have a professor (known as the chairman) who runs
the department.
• Professors work in one or more departments, and for each
department that they work in, a time percentage is associated with
their job.
Chapter 3 Practice Exercises 17

4. Exercise 6
• Graduate students have one major department in which they are
working on their degree.
• Each graduate student has another, more senior graduate student
(known as a student advisor) who advises him or her on what
courses to take.
Draw an ER diagram that captures the information about the university.
Chapter 3 Practice Exercises 18

5. Exercise 6 (solution) SSN PName Age Rank PNo SDate EDate 1 N PROFESSOR
Sponsor
SDate
EDate
MANAGES 1 N
PROFESSOR
PROJECT
Budget
WORKS_ON M N 1 M M
Specialty M 1
RUNS
WORKS_IN
SUPERVISES
WORKS
-ON2 N N
Time 1 N 1
senior 1
MAJOR N
ADVISES
DEPARTMENT
GRAD_STUDENT
Graduate N
DNo
DName
Office
SSN
SName
Age
Degree
Chapter 3 Practice Exercises 19

6. Exercise 4
Identify the entities and relationships for the following description
and draw an ER diagram.
A library system contains libraries, books, authors and patrons, with
identifying attributes library Number, book number, author number,
and patron number, respectively. Libraries are further described by a
library name and location, books by title and page count, authors by
author name, and patrons by patron name and patron weight. Libraries
hold numerous books (some with multiple copies), each authored by
one or more authors. Patrons borrow books, but at any point in time,
may not have anything checked out. When they do have a book
checked out, there is a due date associated with it.
Chapter 3 Tutorial 5

7. Exercise 4 (solution) LibNo LibName BookNo Title 1 HOLDS N LIBRARY
PageCount M N
Location
WRITTEN_BY
CHECK
-OUT
DueDate
AuthorNo N 1
AUTHOR
PATRON
PatronName
AuthorName
PatronNo
PatronWeight
Chapter 3 Tutorial 6

8. Exercise 5
A loan company wants to design a database to track student loans.
Each student attending school is eligible for a loan. A student may
have more than one loan. A student may be registered, possibly at
different times, in more than one school. Each loan should belong to
only one bank. Each bank can approve as many loans as it desires. For each loan, the loan company will track: the student’s SSN, name,
address, amount of loan, date of loan, interest rate ( which may be
different for each loan as determined by the bank), duration of loan,
monthly payment, remaining balance, school ID, school name and
address, number of years the student has been at the school, bank
name, bank branch and bank ID.
Draw an ER diagram.
State any assumptions you make in the diagram.
Chapter 3 Tutorial 7

9. Exercise 5 (solution)
Assumption: each loan to a student (for different
schools) is given a unique LoanId number.
SSN
SName
LoanId
Date
Amount 1
BORROWS N
STUDENT
LOAN
Payment
Duration M
SAddress N
Interest
ATTENDS
APPROVED_BY
NoOfYears
Balance
SchoolName N 1
SCHOOL
BANK
BankName
SchoolId
SchoolAddress
BankId
BankBranch
Chapter 3 Tutorial 8

10. Exercise 2
Consider the ER diagram below. Assume that an employee may work
in up to two departments or may not be assigned to any department.
Assume that each department must have one and may have up to three
phone numbers. Supply (min, max) constraints on this diagram.
State clearly any additional assumptions you make.
(1,50)
1. Each department can have (1-50) employee(s).
(0,2)
WORKS-IN
EMPLOYEE
DEPARTMENT
4. Each employee is assigned (1-5) phone(s).
(1,5)
(1,3)
HAS-PHONE
CONTAINS
PHONE
3. Each phone is assigned to (1-10) employee(s).
(1,10)
2. Each phone is used by only 1 department.
(1,1)
Assumptions:
Chapter 3 Tutorial 3

11. Exercise 3
For each of the following pairs of rules, draw an ER diagram showing the cardinality and participation constraints:
A doctor may treat many patients. A patient may have a designated
doctor for different types of problems.
A hospital has many patient rooms. Each patient room belongs to
that hospital.
An author may write many books. A book may be written by more
than one author.
DOCTOR
PATIENT
TREATS M N
HOSPITAL
ROOM
HAS 1 N
AUTHOR
BOOK
WRITES M N
Chapter 3 Tutorial 4

12. Exercise 6
Consider the following set of requirements for a university database
that is used to keep track of students’ transcripts.
a. The university keeps track of each student’s name, student number,
SSN, current address and phone, permanent address and phone,
birth date, sex, class (freshman, sophomore,...,graduate), major
department, minor department (if any), and degree program
(B.A.,...).Some user applications need to refer to the city, state, and
zip code of the student’s permanent address and to the student’s
last name. Both SSN and student number have unique values for
each student.
b. Each department is described by a name, department code, office
number, office phone, and college. Both name and code have
unique values for each department.
Chapter 3 Tutorial 9

13. Exercise 6
c. Each course has a course name, description, course number,
number of semester hours, level, and offering department. The
value of the course number is unique for each course.
d. Each section has an instructor, semester, year, course, and section
number. The section number distinguishes sections of the same
course that are taught during the same semester/year; its values are
1,2,3,..., up to the number of sections taught during each semester.
e. A grade report has a student, section, letter grade, and numeric
grade (0,1,2,3, or 4).
Design an ER schema for this application, and draw an ER diagram
for that schema. Specify key attributes of each entity type, and
structural constraints on each relationship type. Note any unspecified
requirements, and make appropriate assumptions to make the
specification complete.
Chapter 3 Tutorial 10

14. Exercise 6 (Solution)
Chapter 3 Tutorial 11