Enhanced Entity Relationship Schema

Question 1

IS A

Answer 1

Type of relationship (employee is a user)

Question 2

Inheritance

Answer 2

One entity is derived from another (subclass).
Shown via C connection.

Question 3

Specialisation (top-down)

Answer 3

Attributes/relationships only apply to certain but not all members of entity type

Question 4

Generalisation

Answer 4

Main idea is to suppress differences between entity types
Common features

Question 5

Attribute-defined subclass

Answer 5

Can define what will be inherited.
Outside of connection line.

Question 6

Predicate-defined subclass

Answer 6

The rule that defines it / attribute extended
If subclass is professional, then Job Type (the attribute-defined subclass) = “Professional”

Question 7

Disjoint Constraints

Answer 7

A subclass of a specialisation is disjoint ; comparing the connected subclasses

Question 8

Disjoint

Answer 8

Either one or the other (d)

Question 9

Overlapping

Answer 9

Could be more than one (o)

Question 10

Double line

Answer 10

Must be classified (has to either be salaried or hourly-paid)

Question 11

Single line

Answer 11

Does not need to be an employee or a professional