Extended Entity Relationship

T/F - members of a superclass can be the member of many subclasses

True, subclasses can have existence in multiple entity types

Entities from a subclass inherit ___

all of the above

specialization

set of subclasses derived from a superclass

generalization

combining common features into a superclass

predicate/condition-defined specialization

subclass created are based on the values of an attribute

attribute-defined specialization

subclasses are created based on the name of an attribute

In a EER diagram, subclasses are denoted by ___

C shapes pointing to the superclass

Disjoint constraint

each entity can only appear in at most one subclass, denoted by “d”

Overlapping constraint

each entity can appear in multiple subclasses, , denoted by “o”

total constraint

each entity in the superclass must be in a subclass, denoted by two lines from the superclass

partial constraint

each entity in a superclass can exist outside of the subclasses, denoted by one line from the superclass

An entity that belongs to exactly one subclass has the constraints:

disjoint, total

An entity that may belong to many classes and not necessarily a subclass has the constraints: __

overlapping, partial

An entity that may belong to multiple subclasses only has the constriants ____

overlapping, total

Differentiate single/hirearchy inheritance from multi/lattice inheritance

• single inheritance has only one superclass per subclass

• multi inheritance has multiple superclasses that it inherits all from