![A Relation is a Table ,[object Object],[object Object],[object Object],[object Object],Attributes (column headers) Tuples (rows)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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- 1. The Relational Data Model Tables Schemas Conversion from E/R to Relations
- 7. Relationship -> Relation Drinkers Beers name addr name manf Likes Likes(drinker, beer) Favorite Favorite(drinker, beer) Married husband wife Married(husband, wife) Buddies 1 2 Buddies(name1, name2)
- 11. Example Logins Hosts At name name Hosts(hostName) Logins(loginName, hostName, time) At(loginName, hostName, hostName2) time Must be the same At becomes part of Logins
- 13. Example Beers Ales isa name manf color
- 14. E/R Style name manf Bud Anheuser-Busch Summerbrew Peteâs Beers name color Summerbrew dark Ales
- 15. Using Nulls name manf color Bud Anheuser-Busch NULL Summerbrew Peteâs dark Beers