Entity-Relationship Model
The entity-relationship (ER) model describes the data of an application before any table is designed.
Database Management Systems · topic
ER model
Chen notation for entities, weak entities, relationships and the attribute kinds; cardinality ratio, participation and (min, max) notation; specialization and aggregation; mapping each construct to tables and counting the minimum number of tables.
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Mapping ER Diagrams to Relations
An ER diagram becomes a relational schema by a short list of mechanical rules: one table per strong entity set, one per weak entity set, one per many-to-many relationship, one per multivalued attribute, and foreign keys for everything else.
ER model cheat sheets
One-page visual sheets for this topic, in the sheet library on the store. Previews are free; the full sheets come with the subject pack.