# Question 1. Please select the correct statement(s) regarding a key constraint for a relation. An attribute or set of attributes satisfies a key constraint if there is no duplication of value(s) for such attribute(s) in the relation. A set of attribute(s) S is a key (super key) for a relation R if every pair of tuples in R must disagree on all the values for all attributes in S. A set of attribute(s) S is a key (super key) for a relation R if every pair of tuples in R disagree on at least one value for the attribute(s) in S. None of the above.

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