Entity Relationship Diagram (ERD)? Entity relationship diagram symbols and ER diagram examples.
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An entity relationship diagram (ERD) shows the relationships of entity sets stored in a database. An entity in this context is a component of data. In other words, ER diagrams illustrate the logical structure of databases.
Entity Relationship Diagrams History.
Peter Chen developed ERDs in 1976. Since then Charles Bachman and James Martin have added some slight refinements to the basic ERD principles.
Symbols of ER Diagram