MIS 372 - Ch. 4
Define "Enhanced Entity-Relationship (EER) Model"
The model that has resulted from extending the original E-R model with new modeling constructs.
A subgrouping of the entities in an entity type that is meaningful to the organization and that shares common attributes or relationships distinct for other subgroupings.
A generic entity type that has a relationship with one or more subtypes.
Define "Attribute inheritance"
A property by which subtype entities inherit values of all attributes and instances of all relationships of the supertype.
The process of defining a more general entity type from a set of more specialized entity types.
The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships.
Define "Completeness constraint"
A type of constraint that addresses the question whethe ran instance of a supertype must also be a member of at least one subtype.
Define "Total Specialization Rule"
Specifies that each entity instance of the supertype must be a membe rof some subtype in the relationship.
Define "Partial specialization rule"
Specifies that an instance of the supertype is allowed not to belong to any subtype.
Define "Disjointness Constraint"
"A constraint that addresses the question whether an instance of a supertype may simultaneously be a member of two (or more) subtypes.
Define "Disjoint Rule"
A rule that specifies that an instance of a supertype may not simultaneously be a member of two (or more) subtypes.
Define "Overlap rule"
A rule that specifies that an instance of a supertype may simultaneously be a member of two (or more) subtypes.
Define "Subtype Discriminator"
An attribute of the supertype whose values determine the target subtype or subtypes.
Define "Supertype/subtype hierarchy"
A hierarchical arrangement of supertypes and subtypes, where each subtype has only one supertype.
Define "Entity Cluster"
A set of one or more entity types and associated relationships grouped into a single abstract entity type.
Define "Universal Data Model"
A generic or template data model that can be reused as a starting point for a data modeling project.
A statement derived from other knowledge in the business.
Define "Structural Assertion"
A statement that expresses some aspect of the static structure of the organization.
An operation, such as create, delete, update, or read, which may be performed on data objects.
Define "action assertion"
A statement of a constraint or control on the actions of the organization.
Define "anchor object"
A business rule (a fact) on which actions are limited.
Define "derived fact"
A fact that is derived from business rules using an algorithm or inference.
Define "corresponding object"
A business rule (a fact) that influences the ability to perform an action on another business rule.
MIS 372 - Ch. 4
MIS DB Ch. 4