Functional Dependencies in DBMS

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Question 1

What does the functional dependency A → B mean in DBMS?

  • B uniquely determines A

  • A and B are unrelated

  • A uniquely determines B

  • B is independent of A

Question 2

Which of the following best defines transitive functional dependency?

  • A → B and B → C imply A → C

  • A → B and C → A

  • A → B and B → A

  • A → C directly

Question 3

If X → Y and Y → Z, then according to Armstrong’s Axioms, X → Z is valid due to:

  • Reflexivity

  • Augmentation

  • Union

  • Transitivity

Question 4

What does the functional dependency STUD_NO → STUD_PHONE mean?

  • STUD_PHONE uniquely determines STUD_NO

  • Two students can have the same phone number

  • STUD_NO uniquely determines STUD_PHONE

  • STUD_PHONE and STUD_NO are unrelated

Question 5

If (A → B) and (B → C), then by transitivity which dependency is valid?

  • A → C

  • B → A

  • A → B, C

  • C → A

Question 6

What does the attribute closure help determine?

  • Table structure

  • Prime attributes

  • Derived attributes from a set

  • Insert anomalies

Question 7

What is the main purpose of attribute closure?

  • To find the size of a table

  • To find the primary key

  • Find dependent attributes

  • To enforce foreign key constraints

Question 8

If A → B and B → C, what is (A)+?

  • {A}

  • {A, B}

  • {A, B, C}

  • {A, C}

Question 9

f (X)+ contains all attributes of the relation, what is X?

  • Foreign key

  • Partial key

  • Super key

  • Prime attribute

Question 10

What is the result of computing closure of an empty set of attributes?

  • All attributes

  • Only dependent attributes

  • Nothing

  • The empty set itself

There are 10 questions to complete.

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