Consider a relation schema R = {A, B} and a set of functional dependencies Σ = {A → B}, AB must be a key of R.Question 5Select one:TrueFalse
Question
Consider a relation schema R = {A, B} and a set of functional dependencies Σ = {A → B}, AB must be a key of R.Question 5Select one:TrueFalse
Solution
The statement is True.
Here's the step by step explanation:
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A functional dependency A → B means that for each value of A, there is exactly one value of B associated with it.
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In the given relation schema R = {A, B}, the functional dependency is A → B. This means that the value of A determines the value of B.
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A key in a relation schema is an attribute or a set of attributes that can uniquely identify a tuple (row) in a relation (table).
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Given the functional dependency A → B, it means that A can uniquely determine B. However, we don't have any information about whether B can determine A or not.
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Therefore, to ensure that we can uniquely identify any tuple in the relation, we need to consider both A and B together. Hence, AB must be a key of R.
So, the statement "AB must be a key of R" is true.
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