er-rel - The Relational Data Model Tables Schemas...

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1 The Relational Data Model Tables Schemas Conversion from E/R to Relations
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2 A Relation is a Table name manf Winterbrew Pete’s Bud Lite Anheuser-Busch Beers Attributes (column headers) Tuples (rows)
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3 Schemas Relation schema  = relation name +  attributes, in order (+ types of  attributes). Example: Beers(name, manf) or  Beers(name: string, manf: string) Database  = collection of relations. Database schema  = set of all relation  schemas in the database.
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4 Why Relations? Very simple model. Often  matches how we think about data. Abstract model that underlies SQL, the  most important database language  today. But SQL uses bags, while the relational  model is a set-based model.
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5 From E/R Diagrams to Relations Entity sets become relations with the  same set of attributes. Relationships become relations whose 
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er-rel - The Relational Data Model Tables Schemas...

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