Exam March 2013, questions PDF

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UNIVERSITY EXAMINATION 2017/2018 SCHOOL OF COMPUTING AND INFORMATICS DEPARTMENT OF INFORMATION TECHNOLOGY BIT/BBIT/BAS REGULAR UNIT CODE: BIT1201 DATE: AUGUST, 2018

UNIT TITLE: DATABASE SYSTEMS SPECIAL/SUPP

TIME: 2 HOURS

INSTRUCTIONS: ANSWER ALL QUESTIONS IN SECTION A AND ANY OTHER TWO FROM SECTION B. SECTION A: COMPULSORY QUESTION ONE a) Discuss four threats faced by modern databases.

(4 Marks)

b) Define the term serializability as used in database transaction management (2 Marks) c) Describe the following terms (4 Marks) i. Primary Key ii. Tuple iii. Database iv. Foreign Key d) Discuss the following database languages i. Data Definition Language (DDL) ii. Data Manipulation language (DML) iii. Data Control Language (DCL) Library copy

(3 Marks)

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e) Describe the activities performed during the following phases of database design and development process (8 Marks) i. Requirements Elicitation ii. Conceptual database design iii. Logical database design iv. Physical database design f) Define the term Normalization, and explain its significance in database design and development. (2 Marks) g) Discuss the components of a DBMS environment.

(5 Marks)

h) Distinguish between cardinality and degree of a relation

(2 Marks)

SECTION B: ATTEMPT ANY TWO QUESTIONS FROM THIS SECTION QUESTION TWO a) Study the following database table that stores students records and answer the questions that follows. TABLE: STUDENTS Reg_no 1/2016

First_Name Last_Name Course John Mutuku DCS

Gender Male

D_O_B 13 /6/1990

2/2016

Steve

KipKorir

DCS

Male

13 /3/1985

3/2016

Susan

Mutua

CIT

Female

19 /11/1986

4/2017

Steve

Kingori

DBIT

Male

1/3/1978

Write the following SQL statements to perform the following i. Display all the students where the results will only contain the columns Reg_no, Last_Name and First_Name (2 Marks) ii. To produce the Last_Name and First_Name combined as Student_Name (2 Marks)

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iii. To find the details of all Male students in the course DCS.

(2 Marks)

iv. To produce the total number of students per course.

(2 Marks)

v. Get list all the Male students born between the year 1980 and 1989.

(2 Marks)

vi. Top modify the Last_name of the student Reg_no 4/2017 to Mwangi (3 Marks) vii. To delete all the students records from the table

b) Explain the function of each of the clauses in an SQL statement. i. ii. iii. iv. v.

(2 Marks)

(5 Marks)

WHERE GROUP BY HAVING SELECT ORDER BY

QUESTION THREE a) Describe any four functions of a database administrator.

(4 Marks)

b) Discuss any four major drawbacks associated with file-based system of data storage. (8 Marks) c) Outline four advantages of a Database system.

(8 Marks)

QUESTION FOUR a) The main objective of the ANSI SPARC three level architecture is to separate the user views of the database from it physical representation. Using a diagram to illustration, describe the each of the three levels in this architecture. (9 Marks) b) Discuss the following database normalization levels i. 1ST Normal form ii.2nd Normal form iii.3rd Normal form Library copy

(6 Marks)

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c) Distinguish between Physical Data Independence and Logical Data Independence (4 Marks) d) Explain the term SQL (Structured Query Language) (1 Mark) QUESTION FIVE a) A TV company wishes to develop a database to store data about the TV series that the company produces. The data includes information about actors who play in the series, and directors who direct the episodes of the series. Actors and directors are employed by the company. A TV series are divided into episodes. Each episode may be transmitted at several occasions. An actor is hired to participate in a series, but may participate in many series. Each episode of a series is directed by one of the directors, but different episodes may be directed by different directors. i. Identify all the entities in the above scenario.

(4 Marks)

ii. Draw the Entity relationships diagram to illustrate the relationship between the identified entities (6 Marks) iii. Draw a table diagram for each entity that includes at least three attributes and indicate the primary key attribute (8 Marks) b) Explain the following keys and give examples to illustrate i. Primary key ii. Foreign key

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(2 Marks)

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