given the following entities, which of the choices below would be the most complicated? Automobile: VIN, EngineSize, NumberOfDoors, NumberOfPassengers, FuelType, TransmissionSUV: VIN, EngineSize, NumberOfPassengers, NoWheelDrive, FuelType, TransmissionTruck: VIN, EngineSize, NoWheelDrive, FuelType, Transmission, Payload Show
Sets with similar terms Modern Database Management, 13e (Hoffer) Chapter 3 The Enhanced E-R Model 1) The property by which subtype entities possess the values of all attributes of a supertype is called: A) hierarchy reception. B) class management. C) multiple inheritance. D) attribute inheritance. Answer: D LO: 3.1: Define key terms. Difficulty: Moderate Classification: Concept AACSB: Information Technology 2) Which of the following is a generic entity type that has a relationship with one or more subtypes? A) Megatype B) Supertype C) Subgroup D) Class Answer: B LO: 3.1: Define key terms. Difficulty: Easy Classification: Concept AACSB: Information Technology 3) Given the following entities, which of the choices below would be the most complicated? Automobile: VIN, EngineSize, NumberOfDoors, NumberOfPassengers, FuelType, Transmission SUV: VIN, EngineSize, NumberOfPassengers, NoWheelDrive, FuelType, Transmission Truck: VIN, EngineSize, NoWheelDrive, FuelType, Transmission, Payload A) Define one vehicle entity type to hold all entities. B) Define a separate entity type for each entity. C) Define a supertype called vehicle and make each of the entities subtypes. D) Keep only the Truck entity type. Answer: A LO: 3.2: Recognize when to use supertype/subtype relationships in data modeling. Difficulty: Easy Classification: Concept AACSB: Information Technology What are subtype and supertype entities?A supertype is a generic entity type that has a relationship with one or more subtypes. A subtype is a sub-grouping of the entities in an entity type that is meaningful to the organization and that shares common attributes or relationships distinct from other subgroups.
What are the conditions that must be met for using Supertype subtype relationships?Two conditions that indicate a designer should consider using supertype/subtype relationships: There are attributes that apply to some (but not all) of the instances of an entity type. The instances of a subtype participate in the relationship unique to that subtype.
Which of the following specifies that an entity instance of the supertype does not have to belong to any subtype?Partial specialization rule
Specifies that an entity instance of the supertype is allowed not to belong to any subtype.
What type of constraints in Supertype that an attribute of the supertype whose values determine the target subtype s )?A subtype discriminator is an attribute of the supertype that indicates an entity's subtype. The attribute's values are what determine the target subtype. Disjoint subtypes - simple attributes that must have alternative values to indicate any possible subtypes.
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Choose all valid statements for the generalization approach of supertype and subtype entities
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