Test Papers / Previous Question Papers of IGNOU CS06 (S) Database Management System December 2005

PGDCA / MCA (I Yr)
Term-End Examination

December, 2005

CS06 (S): Database Management System

Time: 3 hours
Maximum Marks: 75

1. (a) Design an ER diagram for all the following relationships. Clearly indicate the entities, relationships and the key constraints. (6)
(i) Each company operates 4 departments, and each department does one functionality
(ii) Each deparlm€nt in part (i) employs one or more employees, and each employee is employed by one department.
(iii) Each of the employees in part (ii) may or may not have one or more dependents, and each dependent belongs to one employee.
(iv) Each employee in part (iii) may or may not have an employment history.

(b) Examine the table shown below : (6)

(i) Why is the table above not in 1NF ?
(ii) Describe the process of normalizing the data shown in the table above to the second normal form (2NF).
(iii) Identify the primary, foreign keys in your 2NF relations.

(c) Explain a B-tree with the help of an example. How is a key inserted in a B-tree ?(5)

(d) Use three reasons for maintaining a data dictionary. (3)

(e) Explain the significance of the following: (3)
(i) Application Programming lnterface
(ii) Remote Procedure Calls

(f) List three functions of a Database Administrator (DBA). (3)

(g) What is the difference between a subquery and a join ? Under what circumstances would you not be able to use a subquery ? (4)

2. (a) What is Indexed sequential file processing? How is it different from Sequential file processing method ? What are tbe disadvantages of Indexed sequential file processing when compared to Multi-key access? (5)

(b) Consider the following relations :
Hotel (hotelNo, name, address)
Room (roomNo, hotelNo, type, price)
Booking (hotelNo, guestNo, dateFrom, dateTo, roomNo)
Guest (guestNo, name, address)

Write the SQL statements for the following :

3. (a) With the help of an example. explain 'client server architecture'. List any two advantages of this approach. Compare the client server architecture with other two approaches. (8)

(b) Explain the need of data replication and data fragmentation with respect to distributed databages. List the differences behreen horizontal and vertical fragmentation. (7)

4. (a) List the differences between the following Join operations: (7)
Equijoin and Natural join
Give example of each join operation to illustrate your answer

(b) What is the purpose of "Null" ? Is a component of a primary key allowed to accept "null" ? Why ? (3)

(c) Explain the semantic net representation in a knowledge-based system with the help of an example. (5)

5. (a) Describe the main aims of conceptual, logical and physical database design phases with the help of an example. (6)

(b) What is a view ? Explain what happens when a user accesses a database through a view. (3)

(c) With the help of an example for each, explain the concepts: (6)
(i) Generalization
(ii) Specialization