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Entity, Entity Set and Entity Type

19 January, 2016 - 14:28

An entity is an object in the real world with an independent existence and can be differentiated from other objects

An entity might be

  • An object with physical existence. E.g. a lecturer, a student, a car
  • An object with conceptual existence. E.g. a course, a job, a position

An Entity Type defines a collection of similar entities.

An Entity Set is a collection of entities of an entity type at a point of time. In ER diagrams, an entity type is represented by a name in a box.

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Figure 8.1 Source: http://cnx.org/content/m28250/latest/