DBMS MCQ Questions And Answers are given here. Based on the questions asked in previous year’s different government and private exams such as CAT, MAT, XAT, NMAT, IIFT, and SNAP. Following MCQs on the database management system for bank exam preparation along with detailed answers will help you to crack most of the questions asked in major exams.
DBMS MCQ Questions And Answers
1. The primary key must be
a) Unique
b) Not null
c) Both Unique and Not null
d) Either Unique or Not null
Answer: c
2. The result of _____unknown is unknown.
a) Xor
b) Or
c) And
d) Not
Answer: d
3. Aggregate functions are functions that take a ___________ as input and return a single value.
a) Collection of values
b) Single value
c) Aggregate value
d) Both Collection of values & Single value
Answer: a
4. All aggregate functions except _____ ignore null values in their input collection.
a) Count(attribute)
b) Count(*)
c) Avg
d) Sum
Answer: b
5. A Boolean data type that can take values true, false, and________
a) 1
b) 0
c) Null
d) Unknown
Answer: d
6. The ____ connective tests for set membership, where the set is a collection of values produced by a select clause. The ____ connective tests for the absence of set membership.
a) Or, in
b) Not in, in
c) In, not in
d) In, or
Answer: c
7. The phrase “greater than at least one” is represented in SQL by _____
a) < all
b) < some
c) > all
d) > some
Answer: d
8. We can test for the nonexistence of tuples in a subquery by using the _____ construct.
a) Not exist
b) Not exists
c) Exists
d) Exist
Answer: b
9. SQL applies predicates in the _______ clause after groups have been formed, so aggregate functions may be used.
a) Group by
b) With
c) Where
d) Having
Answer: b
10. Aggregate functions can be used in the select list or the_______clause of a select statement or subquery. They cannot be used in a ______ clause.
a) Where, having
b) Having, where
c) Group by, having
d) Group by, where
Answer: b
11. The ________ keyword is used to access attributes of preceding tables or subqueries in the from clause.
a) In
b) Lateral
c) Having
d) With
Answer: b
12. Subqueries cannot:
a) Use group by or group functions
b) Retrieve data from a table different from the one in the outer query
c) Join tables
d) Appear in select, update, delete, insert statements.
Answer: c
13. Which of the following is not an aggregate function?
a) Avg
b) Sum
c) With
d) Min
Answer: c
14. The EXISTS keyword will be true if:
a) Any row in the subquery meets the condition only
b) All rows in the subquery fail the condition only
c) Both of these two conditions are met
d) Neither of these two conditions is met
Answer: a
15. How can you find rows that do not match some specified condition?
a) EXISTS
b) Double use of NOT EXISTS
c) NOT EXISTS
d) None of the mentioned
Answer: b
16. A Delete command operates on ______ relation.
a) One
b) Two
c) Several
d) Null
Answer: a
17. Which one of the following deletes all the entries but keeps the structure of the relation.
a) Delete from r where P;
b) Delete from instructor where dept name= ’Finance’;
c) Delete from instructor where salary between 13000 and 15000;
d) Delete from instructor;
Answer: d
18. _________ are useful in SQL update statements, where they can be used in the set clause.
a) Multiple queries
b) Sub queries
c) Update
d) Scalar subqueries
Answer: d
19. The problem of ordering the update in multiple updates is avoided using
a) Set
b) Where
c) Case
d) When
Answer: c
20. The____condition allows a general predicate over the relations being joined.
a) On
b) Using
c) Set
d) Where
Answer: a
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