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
An Entity-Relationship Model, or ER Model, is a conceptual representation of data that typically evolves through three stages: conceptual, logical, and physical. Modelling Business Information: Entity relation...
The associations between entities, such as a Customer "places" an Order . Defines the numerical context of relationships, such as
Countable objects, concepts, or events, such as Customer , Product , or Order . Defines the numerical context of relationships