![]() It is usually drawn in a graphical form as boxes ( entities) that are connected by lines ( relationships) which express the associations and dependencies between entities. ![]() Typically, it represents records of entities and events monitored and directed by business processes, rather than the processes themselves. Some ER models show super and subtype entities connected by generalization-specialization relationships, and an ER model can be used also in the specification of domain-specific ontologies.Īn E–R model is usually the result of systematic analysis to define and describe what data is created and needed by processes in an area of a business. Consequently, the ER model becomes an abstract data model, that defines a data or information structure which can be implemented in a database, typically a relational database.Įntity–relationship modeling was developed for database and design by Peter Chen and published in a 1976 paper, with variants of the idea existing previously, but today it is commonly used for teaching students the basics of data base structure. ![]() ![]() In software engineering, an ER model is commonly formed to represent things a business needs to remember in order to perform business processes. An entity–attribute-relationship diagram for an MMORPG using Chen's notation
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