The Entity Relationship Diagram

The Entity Relationship Diagram (ERD) depicts a conceptual data model that incorporates some of the important scientific information about the real world. It adopts a natural view that the real world consists of entities and relations (Chen, 1976). One objective of the ERD is to create a simple, easy to understand and conveniently presented data model consisting of entities, attributes, relationships and cardinalities. The model serves as tool for database design, where the model can facilitate communication between the system analyst or designer and the end-user during the requirement analysis and conceptual design phases.
Chen published one of the first articles on the entity-relationship model in 1976 at a database conference (Chen, 1976). The concept of entity-relationship already existed for years in the field of philosophy and began to be applied to database design heavily between 1975 and 1980. In 1979, there was a conference on the entity-relationship model during the First International Conference on Entity-Relationship Approach in Los Angeles, California. …