Data Resource Management Exam 1 Chapter 3
What is a supertype?
A generic entity type that has a relationship with one or more subtypes.
Partial Specialization
A rule that specifies that an entity instance of a supertype is allowed not to belong to any subtype.
Disjoint
A rule that specifies that an instance of a supertype may not simultaneously be a member of two or more subtypes.
Overlap
A rule that specifies that an instance of a supertype may simultaneously be a member of two or more subtypes.
Packaged data models
Require customization.
In packaged data models, all subtype/supertype relationships follow the _______ and _______ rules.
total specialization and overlap.
Total Specialization
A rule that specifies that each entity instance of a supertype must be a member of some subtype in the relationship.
What is a subtype?
A subgrouping of the entities in an entity type that has attributes distinct from those in other subgroupings.
The property by which subtype entities possess the values of all attributes of a supertype is called...
Attribute inheritance.
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.
Completeness.
Given the following entities, which of the choices below would be the most complicated?
Define one vehicle entity type to hold all entities.
The process of defining a more general entity type from a set of more specialized entity types is called...
Generalization.
In packaged data models, strong entities always have _____ between them.
M:N relationships
The subtype discriminator in the figure below is...
Part_Type; See quiz 3 number 10.
In the figure below, which of the following are subtypes of patient.
See quiz 3 number 4; outpatient.
The following figure is an example of total specialization.
See quiz 3 number 7.
Entity Cluster
Set of one or more entity types and associated relationships grouped into a single abstract entity type.
The process of defining one or more subtypes of a supertype and forming relationships is called...
Specialization
Which of the following is a generic entity type that has a relationship with one or more subtypes?
Supertype
Generalization
The process of defining a more general entity type from a set of more specialized entity types. BOTTOM UP;
Specialization
The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships; TOP DOWN;
An entity cluster is..
a set of one or more entity types and associated relationships grouped into a single abstract entity type.
An entity cluster can be formed by...
combining a strong entity and its weak entities abstracting a supertype and its subtype combining directly related entity types and their relationships
The most important challenge of customizing a purchased data model is...
determining the business rules that will be established through the data model
In the figure below, the patient must be either an outpatient or a resident patient. This is an example of the _____ rule.
disjoint; see quiz 3 number 9
When identifying with the parts of the packaged data model that apply to your organization, you should first start with...
entities.
Using a packaged data model, projects take less time and cost because...
essential components and structures are already defined.
All of the following are advantages of packaged data models except...
more one-to-one relationships give the data model more flexibility (projects take less time and cost less, the data model is easier to evolve, packaged data models can be built using proven components evolved from cumulative experiences)
A generic or template data model that can be reused as a starting point for a data modeling project is called a
universal data model
