Understanding ER notation

The Entity Relationship model, which describes data in terms of entities, attributes, and relations, was introduced by Peter Pin Shan Chen in 1976. At the same time, he proposed a method of diagramming called Entity Relationship (E/R) diagrams, which has become widely accepted. E/R diagrams use rectangles to describe entities, ellipses for attributes, and diamonds to represent relationships.

E/R diagrams use rectangles to describe entities, ellipses for attributes, and diamonds to represent relationships.