Modelling Business Information: Entity Relation... Online

Introduces specific attributes, primary keys, and foreign keys, mapping out operational data rules without being database-specific.

Countable objects, concepts, or events, such as Customer , Product , or Order . Modelling Business Information: Entity relation...

Defines the numerical context of relationships, such as One-to-One (1:1), One-to-Many (1:N), or Many-to-Many (M:N). The Three Levels of Data Modelling Introduces specific attributes

The associations between entities, such as a Customer "places" an Order . and foreign keys

An Entity-Relationship Model, or ER Model, is a conceptual representation of data that typically evolves through three stages: conceptual, logical, and physical.