Using the Entity Relationship Diagram you have drawn on your piece of paper for the Hamilton Island 'BoatRaceResults' Table, answer the following question.

Which functional dependency shows a Boyce-Codd Dependency in the BoatRaceResults table?

Question

Using the Entity Relationship Diagram you have drawn  on your piece of paper for the Hamilton Island 'BoatRaceResults' Table, answer the following question.

Which functional dependency shows a Boyce-Codd Dependency in the BoatRaceResults table?

BlackTom AI · Accepted Answer

Let's restate the question and options clearly to start our analysis.
Question: Which functional dependency shows a Boyce-Codd Dependency in the BoatRaceResults table?
Answer options:
- A) BoatName --> BoatSaleNum, BoatClub
- B) BoatClub --> ClubSuburb
- C) RaceID --> Division, RaceClass, RaceDate, StartFrom, Skipper
- D) RaceID, BoatName --> Handicap, Place
- E) None exist

Now, evaluate each option against the Boyce-Codd Normal Form (BCNF) requirement, which states that for every non-trivial functional dependency X -> Y in a relation, X must be a superkey (i.e., X functionally determines all attributes of the relation, or at least a candidate key).

Option A: BoatName --> BoatSaleNum, BoatClub
- Would BoatName be a superkey for the BoatRaceResults relation? Likely not, because the same BoatName can appear in multiple races with different BoatSaleNum or associated BoatClub values, so BoatName by itself does not determine all attributes. This FD therefore does not satisfy BCNF and is not a BCNF dependency.

Option B: BoatClub --> ClubSuburb
- Here, BoatClub determines ClubSuburb, but BoatClub is almost certainly not a superkey for the entire BoatRaceResults relation (many boats from the same club share a suburb, but other attributes like RaceID, BoatName, Handicap, etc., are not determined by BoatClub alone). This is a typical partial dependency, not BCNF, so this is not a BCNF dependency.

Option C: RaceID --> Division, RaceClass, RaceDate, StartFrom, Skipper
- This states that RaceID determines several attributes. However, does RaceID determine the entire set of attributes in BoatRaceResults? It does not determine BoatName, BoatSaleNum, BoatClub, ClubSuburb, Handicap, Place, etc., by itself, since those vary per boat within a race. Therefore RaceID alone is not a superkey for the whole relation, so this FD is not BCNF.

Option D: RaceID, BoatName --> Handicap, Place
- The left side here is the combination of RaceID and BoatName, which effectively identifies a specific entry (a particular boat in a particular race). If (RaceID, BoatName) is a candidate key for the relation, then this FD X -> Y has X as a superkey. In many BoatRaceResults schemas, the combination of RaceID and BoatName indeed uniquely identifies the tuple (and thus determines Handicap and Place). Therefore this FD satisfies BCNF.

Option E: None exist
- Given the typical BCNF analysis above, there is at least one BCNF-satisfying dependency (Option D), so this option is not correct.

Summary of reasoning: The BCNF condition requires the left-hand side of the dependency to be a superkey. Among the options, the only left-hand side that functions as a key for the relation is the composite (RaceID, BoatName). It uniquely identifies a specific boat entry within a race and determines the attributes Handicap and Place, making it a BCNF dependency. All other single-attribute determinants (BoatName, BoatClub, RaceID alone) fail to be superkeys for the entire BoatRaceResults relation, so they are not BCNF dependencies.

Using the Entity Relationship Diagram you have drawn on your piece of paper for the Hamilton Island 'BoatRaceResults' Table, answer the following question. Which functional dependency shows a Boyce-Codd Dependency in the BoatRaceResults table?

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