Good luck! This shouldn't take too long. Please don't select the last answer for any of the 3 questions, it's very likely wrong.
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Question 1: Let's use the ER example from section where Persons are related to Books through the "wrote" relationship. We're going to replace our "Person" entity set (where a person may or may not have authored a book) with an "Author" entity set, where each entity is definitely an author of some book. Given the image shown here: http://i.imgur.com/GR2nG.png, what line would best fit between "Authors" and "wrote"?
I just wanted to get this question wrong.
Question 2: Authors have an Id, real Name, Pseudonym, and Age. We _observe_ that all authors in our current table with the same Pseudonym have the same Age. Does this mean there is a functional dependence from Pseudonym --> Age?
Choose the best answer.
Yes, because a functional dependence is defined as an invariant that holds from the left side of the FD to the right, which we see here.
Yes, because a functional dependency holds until proven false by contradictory evidence.
No, because functional dependencies are declared with respect to *all* allowable instances, not just a particular instance of a relation.
No, because functional dependencies must have a key on the left hand side.
I'm not sure, but bunnies sure are cute. Please see: http://i.imgur.com/AfYpE.jpg
Question 3: Our Authors relation has 4 columns, represented as "INPA". We have the functional dependencies I->INPA, N->A. Is this relation in BCNF?
Yes, because all non-trivial FDs are key constraints.
Yes, because we only have trivial FDs.
No, because I->INPA is neither a trivial FD nor a key constraint.
No, because N->A is neither a trivial FD nor a key constraint.
Both, because quantum mechanics.
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