NATIONAL OPEN UNIVERSITY OF NIGERIA
14/16 AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS
SCHOOL OF SCIENCE AND TECHNOLOGY
MARCH/APRIL 2014 EXAMINATION
COURSE CODE: CIT 843
COURSE TITLE: DATABASE MANAGEMENT SYSTEMS
TIME ALLOWED: 2 ½ 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
2. Consider the following “Orders” table:
| OrderId | OrderDate | Price | Customername |
| 11 | 2008/11/12 | 1000 | Henry Bank |
| 21 | 2008/10/23 | 1600 | Niyi Alade |
| 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 SQL statement to:
i) Find the average value of the Price column.
ii) Find the customers that have order Price value higher than the average Price value.
iii) Count the number of orders from “Customer Niyi Alade”.
iv) Find the number of records in the orders table.
3Let us assume that the following staff table (STAFF) has the following records:
| Name | Room | Department | Designation |
| Ajayi | 101 | CIT | Professor |
| Chidi | 201 | ECO | Lecturer I |
| Musa | 202 | ECO | Professor |
| Bello | 301 | CIT | Senior Lecturer |
| Ajayi | 220 | ACC | Senior Lecturer |
Use appropriate selection operators and tabulate the result to:
a. Select only those Staff in the CIT department 4 marks
b. Select only those Staff with last name Ajayi who are professors 4 ½ marks
c. Select only those Staff who are either Professors or in the Economics department
4 ½ marks
d. Select only those Employees who are not in the CIT department or Lecturer I 4 ½ marks
4a. Describe the three levels of data abstraction. 9 marks
b. Explain what is meant by data independence and outline the two types. 6 marks
c. What is a view? 2 ½ marks
5a. 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
6.Explain the following Database recovery terms:
i. Before Image
ii. After image
iii. Rollback
iv. Roll forward
v. Checkpoints
For the 2015 – till date past questions for this course CLICK HERE
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