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Published byAndrew Russell Modified over 9 years ago
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Entity Relationship Diagram
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Introduction Definition: Entity-relationship diagram is a data-modeling technique that visualises entities, the attributes of the entities, and the relationship between entities, within an information system.
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Components Entity Attributes Relationship Cardinality Participation Constraint
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Cardinality Definition: The number of elements in a set or other grouping, as a property of that grouping
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Participation Constraint Definition: specifies whether the existence of an entity depends on its being related to another entity via the relationship type
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Relationship One to one One to many Many to many
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ER Diagram using Crow’s Foot Notation
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Crow’s Foot Notation
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ER Diagram using Chen’s Notation
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Chen’s Notation
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Chen’s notation
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