Database Chapter 3
In the figure below, which of the following are subtypes of patient?
Outpatient
The following figure is an example of:
the overlap rule
Which of the following is a completeness constraint?
Total specialization
In the figure below, to which of the following entities are the entities "CAR" and "TRUCK" generalized?
Vehicle
Which of the following statements is true about the figure shown below?
A rental unit can be an apartment, a house or just a rental unit; it may not be more than one at the same time
Which of the following is a generic entity type that has a relationship with one or more subtypes?
Supertype
The property by which subtype entities possess the values of all attributes of a supertype is called:
attribute inheritance
A(n) _____ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype.
completeness
A(n) _____ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype.
completeness constraint
The _____ rule specifies that an entity can be a member of only one subtype at a time.
disjoint
The process of defining a more general entity type from a set of more specialized entity types is called:
generalization
In the figure below, a student:
must be a graduate student, an undergraduate, a special student or some other type of student
An attribute of the supertype that determines the target subtype(s) is called the:
none of the above.
The _____ rule states that an entity instance can simultaneously be a member of two (or more) subtypes.
overlap
The subtype discriminator is a composite attribute when there is a(n):
overlap rule
The _____ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.
partial specialization
The _____ rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship.
partial specialization
The process of defining one or more subtypes of a supertype and forming relationships is called:
specialization
Subtypes are used when:
there are attributes that apply to some but not all instances of an entity type
Subtypes should be used when:
there are attributes that apply to some but not all instances of an entity type.
The _____ rule specified that each entity instance of the supertype must be a member of some subtype in the relationship.
total specialization
The following figure is an example of:
total specialization
