NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
JANUARY/FEBRUARY 2013 EXAMINATION

Course Code:            CIT 427                                               

Time:  3hrs

Course Title: Database Systems and Management           Course Credit Unit:   3

 Instruction: Answer any five (5) questions.

QUESTIONS

1a. In the context of database systems and management, give a concise description of web services.                                                                                                       (4 marks)

1b. By means of a well-labelled diagram, describe how weather information can be accessed by means of Web services.                                                       (16 marks)

 [Total =20 marks]         

2a. Write down four (4) main elements of an entity-relationship diagram, identifying their corresponding roles.                                                                                    (16 marks)

2b. Describe an empty element in the context of documents                           (4 marks)

[Total =20 marks]

3a. Distinguish between a key constraint and a domain constraint.                  (10 marks)

3b. State two (2) practical approaches for slotting data into a relation.            (10 marks)

[Total =20 marks]

4a. State the three (3) main elements of an SQL expression.                             (12 marks)

4b. Give four (4) reasons why the data definition language is vital in databases.  (8 marks)

     [Total =20 marks]

5a. Write the expression to find the names of all units in a bank relation, if a unit in the unit designated by u.                                                                             (12 marks)       

5b. Identify and state the key role of a select clause.                                        (8 marks)

[Total =20 mark

6a. Enumerate five (5) internal entities of XML specification.               (10 marks)

6b. Write two (2) main functions of the check clause.                           (10 marks)

[Total =20 marks]

7a. Data manipulation can be described based on four (4) different approaches, specify these approaches.                                                                                 (16 marks)

7b. State the syntax for deletion in SQL.                                                                         (4 marks)

[Total =20 marks]