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Comp 401: Database Systems Question Paper
Comp 401: Database Systems
Course:Computer Science
Institution: Chuka University question papers
Exam Year:2012
1
CHUKA UNIVERSITY
COLLEGE
UNIVERSITY EXAMINATIONS
FOURTH YEAR EXAMINATION FOR THE AWARD OF DEGREE OF
BACHELOR OF SCIENCE (COMPUTER SCIENCE)
COMP 401: DATABASE SYSTEMS
STREAM: BSC. (COMP. SC) TIME: 2 HOURS
DAY/DATE: THURSDAY 13/12/2012 8.30 A.M. – 10.30 A.M.
INSTRUCTIONS:
1. Answer question ONE and any other TWO questions
2. Marks are awarded for clear and concise answers
SECTION A-COMPULSORY
Question One (30 Marks)
(a) What do you understand from the following terms [10 marks]
i) Database management system
ii) Normalization
iii) Cardinality
iv) Functional dependencies
v) Database
(b) Briefly describe the three levels of normalization [6 marks]
i) 1NF
ii) 2NF
iii) 3NF
(c) What do you understand from the term indexing [2 marks]
(d) Write an SQL Command to do the following
2
(i) List Name, Registration number and program of a student from a table called
Students [2 marks]
(ii) Produce a statement listing the Regno, Name, Amount paid and date of payment of all payment
transactions a student has made. Amount paid and date of payment is contained in table FEES
and has a foreign key Registration number while Name and program are fields in table
STUDENTS. The relationship between the STUDENTS and FEES table is one to many .
[2 marks]
(e) While giving examples briefly describe the following connectivities
(i) One to one [2 marks]
(ii) One to Many [2 marks]
(iii) Many to Many [2 marks]
(f) What do you understand from the term entity integrity . [2 marks]
SECTION B-ANSWER ANY TWO QUESTIONS FROM THIS SECTION
Question Two (20 marks]
(a) Briefly describe the following four properties of transactions [8 marks]
(i) Atomicity
(ii) Consistency
(iii) Isolation
(iv) Durability
(b) Differentiate between the following database models [8 marks]
(i) Hierarchical
(ii) Network
(iii) Relational
(iv) Object oriented
(c) Database systems exhibit three level architecture/views namely;
Physical level, Logical level and external level.
Differentiate between Logical and external view [4 marks]
3
Question Three (20 Marks)
(a) Based on the form below, produce the normalized tables up to third normal form. [14 marks]
(b) Give Two objectives of Querry processing. [4 marks]
(c)Differentiate between selection operations and Projection operations in Querry processing [2 marks]
Question Four [20 Marks]
A company has a number of employees .The attributes of EMPLOYEE include Employee_ID
(Identifier), Name, Address and Birth_Date.The company has several projects. Attributes of a
PROJECT include Project_ID (Identifier), Project_Name and Start_Date.
Each employee may be assigned to one or more projects or may not be assigned to a project.A project
must have at least one employee assigned and may have any number of employees assigned.
An employee’s billing rate may vary by project and the company wishes to record the applicable billing
rate (Billing_Rate)for each employee when assigned to a particular project.
(a) Do the attributes name in this description follow the guidelines for naming attributes? Explain.If
not suggest better names. [3 marks]
Sales Order
XYZ Company
P.O Box 100
Mombasa
Customer Number 1009 Sales Order
Customer Name: ABC Company Sales Order date
Customer Address: 287 Clerk Number
Nairobi Clerk Name
Item Ordered Description Qty Unit Price Total
800 40 60.00 2,400
801 20 20.00 400
805 10 100 1,000
Order Total 3,800
4
(b) Develop an ER diagram based on the information above and provide good definitions for all the
relationships in this situation. [6 marks]
(c) Transform the conceptual model into corresponding relations and clearly show the relationships
with foreign keys (if available) using arrows. [6 marks]
(d) Explain what do you understand by the term data normalization?.What is the purpose of data
normalization with regard to relations? [5 marks]
Question Five [20 Marks]
(a) Briefly describe the following in relation to distributed database design [6 marks]
(i) Fragmentation
(ii) Allocation
(iii) Replication
(b) While using diagrams describe the following fragmentation types. [8 marks]
(i) Horizontal
(ii) Vertical
(iii)Mixed
(iv) Derived
(c) Briefly describe the following distributed database transparencies [6 marks]
(i) Failure transparency
(ii) Concurrency transparency
(iii) Performance transparency
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