NATIONAL OPEN UNIVERSITY OF NIGERIA
14-16 AHMADU BELLO WAY, VICTORIA ISLAND LAGOS
SCHOOL OF SCIENCE AND TECHNOLOGY
MARCH/APRIL 2015 EXAMINATION
SCHOOL OF SCIENCE AND TECHNOLOGY
Course Code: CIT 843 Course Unit: 3
Course Title: DATABASE MANAGEMENT SYSTEMS
Time Allowed: 2 Hours
Instruction: Answer Any Four Questions
1a. Explain what is meant by database design. 4 marks
b. List five steps of the database design. 7 ½ marks
c. Outline two components of data model. 6 marks
2a. List the basic steps to follow in designing a database application. 10 marks
b. State how to ensure database security at design level. 7 ½ marks
- Explain the following SQL transaction terms:
Lost update problem 5 marks
Dirty read 5 marks
Non-repeatable read 3 marks
Phantom read 4 ½ marks
- Consider the following “Orders” table:
| OrderId | OrderDate | Price | Customer name |
| 11 | 2008/11/12 | 1000 | Henry Bank |
| 21 | 2008/10/23 | 1600 | NiyiAlade |
| 31 | 2008/09/02 | 700 | Henry Bank |
| 41 | 2008/09/03 | 300 | Henry Bank |
| 51 | 2008/08/30 | 2000 | James Adeola |
| 61 | 2008/10/04 | 100 | Niyi Alade |
Write the SQL statement that:
- Find the average value of the Price column.
- Find the customers that have order Price value higher than the average Price value.
- Count the number of orders from “Customer Niyi Alade”
- Count the number of unique customers in the “Orders” table.
4 ½ marks each except (i) with 4 marks
- Explain the following E-R Modelling constructs with an example each:
- Entity 4 ½ marks
- Relationship 4 ½ marks
- Attributes 4 ½ marks
- Identifiers 4 marks
6a. Explain what is meant by DDBMS. 5 marks
b. List the four main dimensions on which DDBMS are classified. 8 marks
c. What is database security? 4 ½ marks
You can get the exam summary answers for this course from 08039407882
Check the sample below
