Homework #2 FAQ
In part (b) what do you mean by the ``object-oriented approach''?
The text discusses ODL and its translation to relations.
However, this is not what we want you to do --- we have deferred ODL
for later in the course.
Rather, just follow the strategy discussed in class for dealing with isa
hierarchies in an ``OO'' style.
Recall the beers-and-ales example.
In part (f), where do the FD's hold?
Sorry -- we meant ``which FD's hold in S(A,B,C)?''
What is a ``counterexample''?
We need to see a relation instance in which the given dependencies hold,
but the proposed dependency does not.
When looking for 4NF violations, do I have to consider implied MVD's?
Alas, yes. For FD's and BCNF, we showed that only the given FD's need to be
However, for 4NF, you need to consider at least the MVD's X->->Y that
follow from the similar-looking FD X->Y.