Which of the following is a generic entity type that has a relationship with one or more subtypes? Show
Given the following entities, which of the choices below would be the most complicated? Automobile: VIN, EngineSize, NumberOfDoors,
NumberOfPassengers, FuelType, Transmission Define one vehicle entity type to hold all entities. The property by which subtype entities possess the values of all attributes of a supertype is called: Subtypes should be used when: there are attributes that apply to some but not all instances of an entity type. The process of defining one or more subtypes of a supertype and forming relationships is called: The process of defining a more general entity type from a set of more specialized entity types is called: Which of the following is a completeness constraint? The ________ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype. The ________ rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship. A ________ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype. The ________ rule specifies that an entity can be a member of only one subtype at a time. A ________ addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes. disjointedness constraint 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.
Which rule specifies that an entity can be a member of only one subtype at a time?Disjoint rule. Specifies that if an entity instance (of the supertype) is a member of one subtype, it cannot simultaneously be a member of two (or more) subtypes. Overlap rule.
What is the property by which subtype entities possess the values of all attributes of a supertype?The property by which subtype entities possess the values of all attributes of a supertype is called: attribute inheritance.
Is a generic entity type that has a relationship with one or more subtypes?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.
|
Is the rule that specifies that an entity instance of a supertype does not have to belong to any subtype?
zusammenhängende Posts
Urheberrechte © © 2024 defrojeostern Inc.
