Chapter3

Question 1

Attribute Inheritance

Answer 1

A property by which subtype entities inherit values of all attributes and instances of all relationships of their supertype; Subtype gets supertype attributes

Question 2

Enhanced entity-relationship model

Answer 2

(EER) A model that has resulted from extending the original E-R model with new modeling constructs

Question 3

Partial Specialization Rule

Answer 3

A rule that specifies that an entity instance of a supertype is allowed not to belong to any subtype

Question 4

Disjointness constraint

Answer 4

A constraint that addresses whether an instance of a supertype may simultaneously be a member of two (or more) subtypes

Question 5

Generalization

Answer 5

The process of defining a more general type from a set of more specialized entity types; Creating a supertype for entity types (down up)

Question 6

Total specialization rule

Answer 6

A rule that specifies that each entity instance of a supertype must be a member of some subtype in the relations hip

Question 7

Completeness constraint

Answer 7

A type of constraint that addresses whether an instance of a supertype must also be a member of at least one subtype

Question 8

Specialization

Answer 8

The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships: Creating subtype for an entity type (top down)

Question 9

Supertype

Answer 9

A generic entity type that has a relationship with one or more subtypes; Generalized entity type

Question 10

Disjoint Rule

Answer 10

A rule that specifies that an instance of a supertype may not simultaneously be a member of two (or more) subtypes

Question 11

Overlap Rule

Answer 11

A rule that specifies that an instance of a supertype may simultaneously be a member of two (or more) subtypes

Question 12

Entity Cluster

Answer 12

A set of one or more entity types and associated relationships grouped into a single abstract entity type

Question 13

Subtype

Answer 13

A subgrouping of the entities in an entity type that is meaningful to the organization and that shares common attributes or relationships distinct from other subgroupings; Subset of Supertype

Question 14

Universal data model

Answer 14

A generic or template data model that can be reused as a starting point for a data modeling project

Question 15

Supertype/subtype hierarchy

Answer 15

A hierarchical arrangement of supertypes and subtypes in which each subtype has only one supertype