entity-relationship modelrequirements 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