First-Term Examination

Fifth Semester [B.Tech] - September 2005

Paper Code : ETCS – 309 Subject : *Database Management Systems*

Time : 1¹/₂ Hours

Maximum Marks : 30

Note : Attempt any 3 questions in all. Q1 is compulsory. Each question carries 10 marks.

Q1	( a )	What is the primary goal of DBMS?	5x2
	( b )	What are the components of query processor?
	( c )	Distinguish between a weak entity set and a strong entity set.
	( d )	Define the concept of aggregation with an example.
	( e )	Differentiate between DDL and DML.

Q2	( a )	What are the five main functions of database administrator?	5
	( b )	What is a storage manager? List and explain the main components of a storage manager.	5

Q3	( a )	Distinguish between primary key, candidate key and super key.	3
	( b )	How are composite and multi-valued attributes represented in an ER diagram?	2
	( c )	A database is being constructed to keep track of the teams and games of a sports league. A team has a number of players, not all of whom participate in each game. It is desired to keep track of the players participating in each game for each team, the position they played in that game and the result of the game. Design an ER diagram for this application stating clearly the assumptions made. Choose your favorite game (baseball, cricket...).	5

( a )

Consider the following relations for a database that keeps track of business trips of salespersons in a sales office:

Salesperson (SSN, Name, Start-year, Dept-no)
Trip (SSN, From-city, To-city, Departure-date, Return-date, Trip-id)
Expense (Trip-id, Account#, Amount)

Specify the following queries in relational algebra:

a) Give the details (all attributes of trip relation) for trips that exceed Rs 2000/- in expenses.
b) Print the SSN of the salesmen who took trips to 'Nepal'.
c) Print the total trip expenses incurred by the salesman with SSN='200'

3x2

( b )

What are the commonly used aggregate functions used in Relational Algebra?

( c )

Explain the following expressions in relational algebra:

1) Outer join
2) Natural join

1+1