Relational Model
Relations, keys and constraints — and how an ER diagram becomes actual tables.
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Candidate key or superkey?
Foundation
- Not triedCandidate key or superkey?Foundation
- Not triedThe delete the database refusedFoundation
- Not triedWhat a primary key is forFoundation
- Not triedWhat does a foreign key do?Foundation
- Not triedWhat NULL actually meansFoundation
- Not triedEnforcing it in the application insteadCore
- Not triedNothing is ever deletedCore
- Not triedThe meeting that moved by five and a half hoursCore
- Not triedThe migration that took the site downChallenge