SUNSHINE AIRLINE COMPANY
The ER Diagram for the SUNSHINE AIRLINE COMPANY is based on the following:
- For each airplane type, we keep track of a unique airplane type ID (AirplaneTypeID), number of engines (NoOfEngines), and number of seats (NoOfSeats).
- For each airport, we keep track of a unique airport ID (AirportID), and the length of the main runway (LengthOfRunway).
- Each airplane type is able to land at one airport at least, but may be able to land at many airports. Each airport accommodates landing of at least one airplane type, but may accommodate landing of more airplane types.

In the ER Diagram for the SUNSHINE AIRLINE COMPANY, which word should replace qqq?

Question

SUNSHINE AIRLINE COMPANY
The ER Diagram for the SUNSHINE AIRLINE COMPANY is based on the following:
- For each airplane type, we keep track of a unique airplane type ID (AirplaneTypeID), number of engines (NoOfEngines), and number of seats (NoOfSeats).
- For each airport, we keep track of a unique airport ID (AirportID), and the length of the main runway (LengthOfRunway).
- Each airplane type is able to land at one airport at least, but may be able to land at many airports. Each airport accommodates landing of at least one airplane type, but may accommodate landing of more airplane types.

In the ER Diagram for the SUNSHINE AIRLINE COMPANY, which word should replace qqq?

BlackTom AI · Accepted Answer

The question provides key details of the SUNSHINE AIRLINE COMPANY ERD: for each airplane type we store AirplaneTypeID, NoOfEngines, and NoOfSeats; for each airport we store AirportID and LengthOfRunway; and relationships indicate that airplane types land at airports and each airport handles at least one airplane type. Now, evaluate each option to determine what should replace qqq.
Option 1: AirplaneTypeID. This would be a plausible identifier attribute for the airplane type entity, not for the airport side. If qqq were meant to describe an attribute of the airplane side in the diagram, AirplaneTypeID would belong with the airplane type entity (AAA), not with the airport (BBB). However, the description already assigns AirplaneTypeID to the airplane-type data, so duplicating it as qqq on the airport side would be inconsistent with the given labeling scheme.
Option 2: AirportID. Since the airport entity must have its own unique identifier, and the figure shows a separate airport-related attribute cluster on the right side (BBB), placing AirportID there would align with the notion that the right-hand side represents the airport entity. It also matches the statement that airports are identified by a unique ID, which is exactly what AirportID conveys.
Option 3: LengthOfRunway. This attribute is explicitly tied to airports in the description. It would belong under the airport entity’s attribute set rather than as a placeholder on the relationship side. If qqq were intended to capture a property of the airport, LengthOfRunway would be the natural placement on the airport side, but the question already includes LengthOfRunway elsewhere in the stated attributes, so duplicating it here would be redundant.
Option 4: NoOfEngines. This is clearly an attribute of the airplane type, not the airport. Assigning NoOfEngines to the airport side would misrepresent the data model, since engines pertain to aircraft characteristics, not airport infrastructure.
Option 5: NoOfSeats. Similar to NoOfEngines, this is an airplane-type attribute (capacity) and does not describe an airport property. Placing it on the airport side would blur the distinction between aircraft characteristics and airport facilities.
In summary, among the options, AirportID best satisfies the role of an identifier for the airport entity on the right-hand side (BBB) of the ERD, consistent with the description that airports have a unique AirportID and that the right entity represents airports. The other options either duplicate airplane-type attributes, correspond to properties that belong to the airplane type, or describe airport properties that are already defined elsewhere in the model.

MISM3403.16575.202610 Exam 2

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