4.1

Entity Relation Model

A high-level representation of data requirements that ignores implementation details.

Entity Type

A set of things that share common attributes.

Relationship Type

A set of related things that defines how entities are associated.

Attribute Type

A set of values that describe the properties of an entity.

Reflexive Relationship

A relationship that relates an entity to itself.

ERD

Entity-Relationship Diagram, a visual representation of the entity relationship model.

Conceptual Design

Phase that develops an entity relationship model capturing data requirements, ignoring implementation details.

Logical Design

Phase that converts the ER model into tables, columns, and keys for a specific database system.

Physical Design

Phase that adds indexes and specifies how tables are organized on storage media.

Attribute Instance

An individual value associated with an attribute.

Relationship Instance

A statement about entity instances.

Entity Instance

An individual thing within an entity type.