NPTEL Data Base Management System Week 1 Assignment Answers 2025
1. Which of the following statements is (are) incorrect?
a) Logical level abstraction defines the physical storage of data.
b) View level abstraction provides a user-friendly interface for end users.
c) Physical level abstraction focuses on the relationships among data.
d) Logical level abstraction focuses on the relationships among data.
Answer :- a, c
2. Consider the following SQL statements):
S1:
INSERT INTO employees(emp_id, emp_name, dept)
VALUES (101, ‘Alice’, ‘HR’);
S2:
ALTER TABLE employees ADD COLUMN salary number (8, 2); Identify the correct statement.
a) Both S1 and S2 are Data Manipulation (DML) Queries
b) S1 is a Data Manipulation (DML) Query, and S2 is a Data Definition (DDL) Query
c) Both S1 and S2 are Data Definition (DDL) Queries
d) S1 is a Data Control Query, and S2 is a Data Definition (DDL) Query
Answer :- b
3.
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4. Identify the correct statement/s.
a) Employee(empID, empName) is an instance of a relation schema.
b) Employee(empID, empName) is an example of a physical schema.
C) (101, John) is an instance of a relation schema.
d) (101, John) is an example of a logical schema.
Answer :-
5. Consider a relation CityDetails(CityName, Population, CountryName) where the superkeys are as
follows: (CityName}, {CityName, Population), {CityName, CountryName}, {CityName, Population, CountryName }.
Select the possible candidate key(s).
a) {CityName, Population, Country Name}
b) {CityName, Population)
c) {CityName}
d) {CityName, Country Name}
Answer :-
6. Consider the following relations:
Employee (eid, ename, salary)
Department (did, eid)
Consider the following Relational Algebras:
RA1: lEmployee.eid, ename (Employee X Department)
RA2: lEmployee.eid, ename Employee x Department)
Which of the following is correct?
a) RA1 = RA2
b) RA1 C RA2
c) RA2 E RA1
d) RA1 & RA2
Answer :-
7.
Answer :-
8.
Answer :-
9.
Answer :-
10.
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