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Welcome to the DBMS MCQs Page

Dive deep into the fascinating world of DBMS with our comprehensive set of Multiple-Choice Questions (MCQs). This page is dedicated to exploring the fundamental concepts and intricacies of DBMS, a crucial aspect of UGC CBSE NET Exam. In this section, you will encounter a diverse range of MCQs that cover various aspects of DBMS, from the basic principles to advanced topics. Each question is thoughtfully crafted to challenge your knowledge and deepen your understanding of this critical subcategory within UGC CBSE NET Exam.

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Check out the MCQs below to embark on an enriching journey through DBMS. Test your knowledge, expand your horizons, and solidify your grasp on this vital area of UGC CBSE NET Exam.

Note: Each MCQ comes with multiple answer choices. Select the most appropriate option and test your understanding of DBMS. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

DBMS MCQs | Page 8 of 23

Q71.
Consider the following ORACLE relations:

One (x, y) = {<2, 5>, <1, 6>, <1, 6>, <1, 6>, <4, 8>, <4, 8>}
Two (x, y) = {<2, 55>, <1, 1>, <4, 4>, <1, 6>, <4, 8>, <4, 8>, <9, 9>, <1, 6>}

Consider the following two SQL queries SQ1 and SQ2:

SQ1 : SELECT * FROM One)
EXCEPT
(SELECT * FROM Two);

SQ2 : SELECT * FROM One)
EXCEPT ALL
(SELECT * FROM Two);

For each of the SQL queries, what is the cardinality (number of rows) of the result obtained when applied to the instances above?
Discuss
Answer: (b).1 and 2 respectively
Q72.
Which one of the following pairs is correctly matched in the context of database design?

List – I                                       List – II
(Database term)                      (Definition)

I. Specialization                       A. Result of taking the union of two or more
disjoint (lower-level) entity sets to produce
a higher-level entity set.
II. Generalization                    B. Express the number of entities to which another
entity can be associated via a relationship set.
III. Aggregation                       C. Result of taking a subset of a higher-level
entity set to form a lower-level entity set.
IV. Mapping cardinalities      D. An abstraction in which relationship sets (along
with their associated entity sets) are treated as
higher-level entity sets, and can participate in
relationships.
Codes :
      I    II   III   IV
Discuss
Answer: (d).C  A   D   B
Q73.
Consider a hash table of size m = 10000, and the hash function h(K)=floor(m(KAmod1)) for A = (√5 – 1)/2. The key 123456 is mapped to location ...............
Discuss
Answer: (b).41
Discuss
Answer: (c).Object-oriented databases are more adapt at handling structures (analytical) data than relational databases.
Q75.
In distributed databases, location transparency allows for database users, programmers and administrators to treat the data as if it is at one location. A SQL query with location transparency needs to specify:
Discuss
Answer: (b).Fragments
Q76.
Consider the relations R(A,B) and S(B,C) and the following four relational algebra queries over R and S:

I. πA,B(R⋈S)
II. R⋈πB(S)
III. R∩(πA(R) Χ πB(S))
IV. πA,R.B(R Χ S) where R.B refers to the column B in table R.

One can determine that:
Discuss
Answer: (d).I, III and III are the same query.
Q77.
Which of the following statements is TRUE?

D1: The decomposition of the schema R(A,B,C) into R1(A,B) and R2(A,C) is always lossless.
D2: The decomposition of the schema R(A,B,C,D,E) having AD→B, C→DE, B→AE, AE→C into R1(A,B,D) and R2(A,C,D,E) is lossless.
Discuss
Answer: (d).Only D2
Q78.
Consider the following ORACLE relations:

R(A,B,C) = {<1,2,3>, <1,2,0>, <1,3,1>, <6,2,3>, <1,4,2>, <3,1,4>}
S(B,C,D) = {<2,3,7>, <1,4,5>, <1,2,3>, <2,3,4>, <3,1,4>}

Consider the following two SQL queries SQ1 and SQ2:

SQ1: SELECT R.B, AVG(S.B)
FROM R, S
WHERE R.A = S.C AND S.D < 7
GROUP BY R.B;

SQ2: SELECT DISTINCT S.B, MIN (S.C)
FROM S
GROUP BY S.B
HAVING COUNT (DISTINCT S.D) > 1;

If M is the number of tuples returned by SQ1 and N is the number of tuples returned by SQ2 then
Discuss
Answer: (a).M=4, N=2
Discuss
Answer: (c).Only the joining attributes are sent from one site to another and then only the required rows are returned.
Q80.
Consider a “CUSTOMERS” database table having a column “CITY” filled with all the names of Indian cities (in capital letters). The SQL statement that finds all cities that have “GAR” somewhere in its name, is:
Discuss
Answer: (c).Select *from customers where city like ‘%GAR%’;

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