4. Extended ER Model

Question 1

enhanced ER (EER)

Answer 1

additional semantic data modeling concepts (e.g. knowledge representation and object modeling)

Question 2

subclass

Answer 2

set of entities in each grouping that belong to another entity set

Question 3

superclass

Answer 3

entity type that has subclasses

Question 4

type inheritance

Answer 4

entity that is a member of a subclass inherits all attributes of the entity as a member of the superclass (and relationships)

Question 5

specialization

Answer 5

the process of defining a set of subclasses of an entity type (the superclass of the specialization)

Question 6

generalization

Answer 6

process of defining a generalized entity type from the given entity types

Question 7

predicate (condition-) defined subclass

Answer 7

predefined subclasses by placing condition ont he value of some attribute of the superclass (defining predicate)

Question 8

attribute-defined specialization

Answer 8

if all subclass in a specialization have their membership condition on the same attribute of the superclass (defining attribute)

Question 9

user-defined subclass

Answer 9

if no condition for determining membership in subclass

Question 10

disjointness constraint

Answer 10

specifies that the subclasses of the specialization must be disjoint (at most one subclass), otherwise overlapping

Question 11

completeness constraint

Answer 11

total if every entity in the superclass must be a member of at least one subclass in the specialization, otherwise partial

Question 12

specialization hierarchy

Answer 12

each subclass has only one parent