pls help me to find out non trivial functional dependency in a following table?
A. B. C
1 1 1
1 1 0
2 3 2
2 3 2
and also explain the basic concept behind it. thank you,,
A functional dependency answers the question, "Given one value for X, do I find one and only one value for Y?" Both X and Y are sets; each one represents one or more attributes.
So we can ask ourselves, "Given one value for 'A', do I find one and only one value for 'B'?" And the answer is "Yes". (Assuming the sample data is representative.) That leads to the nontrivial functional dependency A->B.
And we continue with the question, "Given one value for 'A', do I find one and only one value for 'C'?" And the answer is "No". Given 1 for 'A', we find two different values for 'C': 1 and 0. No functional dependency there.
Repeat for every possible combination of attributes.