An Entity Relationship Diagram is an illustration of different data using conventions that describe how these data are related to one another. There are two different notations for entity relationship diagrams, Chens Database Notation and Crows Foot Database Notation. Within Chens Database the entity is represented by a rectangle, while their attributes are represented by a circle and their relationship by a diamond. Relationships in Crows Foot Notation are represented by an arrow with the relationship labeling the arrow. Entity Relationship diagrams make it easy for businesses to quickly identify what entities are interacting with one another and how within the day to day processes of a business. Cardinality describes how relationships are related to one another. For example, you can have 1:1 relationships, 1:many, and many:many.
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