Database Questions and Answers – Set Operations

This set of Database Multiple Choice Questions & Answers (MCQs) focuses on “Set Operations”.

1. The union operation is represented by
a) ∩
b) U
c) –
d) *
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2. The intersection operator is used to get the _____ tuples.
a) Different
b) Common
c) All
d) Repeating
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3. The union operation automatically __________ unlike the select clause.
a) Adds tuples
b) Eliminates unique tuples
c) Adds common tuples
d) Eliminates duplicate
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4. If we want to retain all duplicates, we must write ________ in place of union.
a) Union all
b) Union some
c) Intersect all
d) Intersect some
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5.

(SELECT course id
FROM SECTION
WHERE semester = ’Fall’ AND YEAR= 2009)
EXCEPT
(SELECT course id
FROM SECTION
WHERE semester = ’Spring’ AND YEAR= 2010);

This query displays
a) Only tuples from second part
b) Only tuples from the first part which has the tuples from second part
c) Tuples from both the parts
d) Tuples from first part which do not have second part
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6. For like predicate which of the following is true.

i) % matches zero OF more characters.
ii) _ matches exactly one CHARACTER.

a) i-only
b) ii-only
c) i & ii
d) None of the mentioned
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7. The number of attributes in relation is called as its
a) Cardinality
b) Degree
c) Tuples
d) Entity
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8. _____ clause is an additional filter that is applied to the result.
a) Select
b) Group-by
c) Having
d) Order by
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9. _________ joins are SQL server default
a) Outer
b) Inner
c) Equi
d) None of the mentioned
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10. The _____________ is essentially used to search for patterns in target string.
a) Like Predicate
b) Null Predicate
c) In Predicate
d) Out Predicate
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Sanfoundry Global Education & Learning Series – Database Management System.