ER - crow's foot
Data modelling: ER and crow's foot notation
Entity-relationship modelling in crow's foot notation, and the trip from a conceptual sketch to a schema a database will actually accept.
3 articles28 min read
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Entity-relationship diagrams
How to read and draw an entity-relationship diagram: entities, attributes, primary and foreign keys, relationships and cardinality in crow's foot notation, the conceptual-logical-physical progression, and how an ER model differs from a UML class diagram.
9 min read
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Data models and the diagrams that carry them
- 02Crow's foot notationThe crow's foot cardinality symbols in full: one, many, zero, and the pairs they form; which end of the line each symbol constrains; identifying versus non-identifying relationships; resolving many-to-many; and how crow's foot compares with Chen and with UML multiplicity.Notation reference8 min read
- 03Schema designTurning an ER model into a schema a database will accept: choosing keys, normalizing to third normal form with a worked example, when denormalization is justified, implementing inheritance, and generating DDL from the diagram.Modelling practice11 min read
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