entity-relationship diagram from FOLDOC

ER ⇝

entity-relationship diagram

A visual representation of an entity-relationship model.

An entity-relationship diagram has a box for each entity, containing its properties, and lines between boxes for relationships. The ends of the lines are labelled to show the type of relationship - one-to-one, one-to-many or many-to-many.

Last updated: 2019-11-03

ER ⇝

entity-relationship model

<data, database, specification>

The most common kind of data modelling, proposed by Peter P. Chen in 1976, in which a database is divided into "entities" and "relations".

Part of capturing the requirements of an application is defining the entities involved and their relationships. Together, these form an entity-relationship model.

Entities are the kinds of things or concepts the application deals with, e.g. products, customers, sales transactions. A relationship connects two entities and says how many instances of each participate in the relationship - one-to-one, one-to-many or many-to-many.

Entities and some relationships correspond to database tables. A table corresponding to a relationship is also known as a "join table" after the join database operation.

A model is represented graphically as an entity-relationship diagram.

["The entity-relationship model: toward a unified view of data", P.P. Chen, ACM Transactions on Database Systems 1:1 pp 9-36, 1976].

Last updated: 2019-11-03

Nearby terms:

entity ♦ entity-relationship diagram ♦ entity-relationship model

Try this search on Wikipedia, Wiktionary, Google, OneLook.