Functional Dependency

Question

Validity of third statement

Comments

Yes third statement is true.

Unique key can be NULL and we can apply it on more than one attributes in the same table also.

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@ Ashwin Kulkarni  Here in third statement after and the term "unique" key is referring to PRIMARY or ALTERNATIVE key?

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It is referring to alternative key.

If we consider unique key as primary key then that statement will false. But they have explicitly mentioned alternative key hence i have taken that.

Answer 1

1)FALSE

2)FALSE

3)TRUE