DBIT 301  DIT 205 PRINCIPLES OF DATABASE DESIGN.

UNIVERSITY EXAMINATIONS: 2017/2018
EXAMINATION FOR THE DIPLOMA IN BUSINESS INFORMATION
TECHNOLOGY & DIPLOMA IN INFORMATION TECHNOLOGY
DBIT 301 & DIT 205: PRINCIPLES OF DATABASE DESIGN
DATE: DECEMBER, 2017 TIME: 1 ½ HOURS
INSTRUCTIONS: Answer Question One and Any Other Two Questions.

QUESTION ONE [20 MARKS]
(a) List and briefly describe five components of a database system [10 Marks]
(b) State three limitations of database systems [3 Marks]
(c) With the aid of a diagram, describe the following database models:-
(i) Hierarchical model
(ii) Flat model [9 Marks]
(d) State three advantages and two disadvantages of a relational database model [5 Marks]
(e) In the context of a relational database model, define the following keys: – [3 Marks]
(i) Candidate key
(ii) Primary key
(iii) Foreign key
QUESTION TWO [20 MARKS]
(a) Explain five problems associated with traditional file processing systems [5 Marks]
(b) Explain four application areas of database systems [8 Marks ]
(c) A new database system is to be implemented in an organization. Identify three issues that
should be addressed in order to ensure minimal staff resistance [3 Marks]
(d) Distinguish between the following terms:- [4 Marks]
Page 1 of 3
(i) DBMS & database
(ii) File & record
QUESTION THREE [20 MARKS]
(a) Distinguish between alter table and drop table commands as used in MYSQL [2 Marks]
(b) Table one below shows the product sales for the year ended 31st December 2016
Year Tomatoes carrots onions
2000 30,000 2000 340
2010 30,000 6,000 4000
2016 36,000 3,400 6500
2014 3,000 3900 2600
Table one
Required:
Write MYSQL commands that can be used to carry out each of the following operations:-
Use wakulima as the name of the table
(i) Compute the total amount earned from onions sales [3 Marks]
(ii) Compute the average total sales for tomatoes [3 Marks]
(iii) Delete the product records for 2016 from the wakulima table [3
Marks]
(iv)Display the lowest sales earned from tomatoes [3 Marks]
(v) Create the database system named ‘Sales’ [2 Marks]
(c) Explain the term ‘view’ as used in database systems [2 Marks]
(d) Describe any two objects in a database system [2 Marks]
QUESTION FOUR [20 MARKS]
(a) (i) Explain the term ‘functional system requirements’ as used in computerized information
systems [2 Marks]
(ii)Using a computerized payroll system as an example, give five examples of functional
requirements [5 Marks]
(b) Explain the following data models: – [4 Marks]
(i) Conceptual model
(ii) Logical model
(c) Table 2 shows an invoice generated by an inventory system. Use it to answer the questions
that follow:-
Customer Number:……………………………….. Customer
Name………
Physical address:………………………………….. Cell
phone:………………
Invoice No Date of delivery Type Amount
Table 2
Required:
(i) Define the term ‘normalization’ [2 Marks]
(ii) Normalize the data in the invoice to the 3rd Normal Form [7 Marks]
QUESTION FIVE [20 MARKS]
(a) List and briefly describe four essential features of a good database system [8 Marks]
(b) Outline four key responsibilities of a Database Administrator (DBA) [4 Marks]
(c) Explain four DML commands support by a DBMS [8 Marks ]

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