Modern Database Management - Chapter 3
disjointedness constraint
A ________ addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes.
completeness
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.
universal data model.
A generic or template data model that can be reused as a starting point for a data modeling project is called a(n):
data profiling.
A good method for identifying inconsistencies and finding hidden meaning in the customized purchased data model is:
more one-to-one relationships give the data model more flexibility.
All of the following are advantages of packaged data models EXCEPT:
utilize all business rules that come with the packaged data model.
All of the following are steps to using a packaged data model EXCEPT:
none of the above.
An attribute of the supertype that determines the target subtype(s) is called the:
all of the above.
An entity cluster can be formed by:
a set of one or more entity types and associated relationships grouped into a single abstract entity type.
An entity cluster is:
only one supertype.
In a supertype/subtype hierarchy, each subtype has:
supertypes
In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all ________ in the hierarchy.
total specialization and overlap
In packaged data models, all subtype/supertype relationships follow the ________ and ________ rules.
M:N relationships
In packaged data models, strong entities always have ________ between them.
require customization.
Packaged data models:
there are attributes that apply to some but not all instances of an entity type.
Subtypes should be used when:
disjoint
The ________ rule specifies that an entity can be a member of only one subtype at a time.
partial specialization
The ________ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.
total specialization
The ________ rule specifies that each entity instance of the supertype must be a member of some subtype in the relationship.
overlap
The ________ rule states that an entity instance can simultaneously be a member of two (or more) subtypes.
determining the business rules that will be established through the data model.
The most important challenge of customizing a purchased data model is:
generalization.
The process of defining a more general entity type from a set of more specialized entity types is called:
specialization.
The process of defining one or more subtypes of a supertype and forming relationships is called:
attribute inheritance.
The property by which subtype entities possess the values of all attributes of a supertype is called:
overlap rule.
The subtype discriminator is a composite attribute when there is a(n):
map data to be used from package to data in current databases.
The third step in the data modeling process with a packaged data model is:
essential components and structures are already defined.
Using a packaged data model, projects take less time and cost because:
entities.
When identifying with the parts of the packaged data model that apply to your organization, you should first start with:
Total specialization
Which of the following is a completeness constraint?
Supertype
Which of the following is a generic entity type that has a relationship with one or more subtypes?