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Question

Read the below passage and answer the questions Functional dependency A B means that B is dependent on A i.e. from the value of A we can find the value of B from the relation. Therefore, to prove A B holds in a relation, one of the following conditions must be true: Condition1: either all the value of A must be unique Or Condition2: all the value of B must be same Or Condition3: If two or more tuples/rows of the relation have same value for attribute A then there must be also same value for attribute B i.e. if t1[A] = t2[A] then there must be t1[B] = t2[B].

Which functional dependency does not holds in given relation and why?

A 1 Correct Answer Incorrect Answer
B 2 Correct Answer Incorrect Answer
C 3 Correct Answer Incorrect Answer
D None of these Correct Answer Incorrect Answer
E All of these Correct Answer Incorrect Answer

Solution

v->wx satisfies condition 3 i.e. value of v is repeated 3 times ( 7 ) then value of wx is also repeated . so option 1 is correct. yz->x satisfies condition 2, i.e. all values of x are same, so option 2 is correct. x ->yz does not satisfy any of the three conditions, so option 3 is incorrect.

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