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

Which are Dependent Non-Key Attributes of 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 are Dependent Non-Key Attributes of the BoatRaceResults table?

BlackTom AI · Accepted Answer

First, restate what the question is asking in our own words: which attributes in the BoatRaceResults table are dependent non-key attributes? Recall that a dependent non-key attribute is a column that is not part of the primary key and is functionally determined by the primary key (or by a combination of key attributes).

Option 1: BoatClub, ClubSuburb. These are related through a transitive chain (BoatName -> BoatClub and BoatClub -> ClubSuburb) but neither BoatClub nor ClubSuburb is shown to be directly dependent on the BoatRaceResults composite key (RaceID + BoatName) in the given functional dependencies. They are more like a separate chain of dependencies starting with BoatName, not direct dependents of the primary key.

Option 2: Handicap, Place. The functional dependencies given include RaceID, BoatName -> Handicap, Place, Skipper. This means Handicap and Place are determined by the combination of RaceID and BoatName, i.e., by the primary key (or by the key components together). Since they are not part of the primary key themselves, they are non-key attributes that depend on the key. This matches the definition of dependent non-key attributes.

Option 3: RaceID, BoatName. These two fields together actually form the composite primary key for the BoatRaceResults table (as implied by the dependency RaceID, BoatName -> ...). They are key attributes, not non-key attributes, so they cannot be the dependent non-key attributes.

Option 4: RaceID, RaceDate. RaceDate depends on RaceID (RaceID -> RaceDate) according to the dependencies, but RaceDate is not a non-key attribute in the context of the BoatRaceResults table’s primary key; instead, RaceDate is functionally determined by RaceID alone, which is part of the key. However, since the question asks for dependent non-key attributes of BoatRaceResults, and RaceDate is not listed as a non-key attribute dependent on the full key in the provided dependencies, this option does not correctly identify the dependent non-key attributes here.

Putting it together, the only pair that fits the definition of dependent non-key attributes given the dependencies is Handicap and Place, which are determined by the key (RaceID, BoatName) and are not themselves key attributes.

Using the Entity Relationship Diagram you have drawn on your piece of paper for the Hamilton Island 'BoatRaceResults' Table, answer the following question. Which are Dependent Non-Key Attributes of the BoatRaceResults table?

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