Update Anomalies and Functional Dependencies
When one fact is stored in many rows, the table starts to contradict itself, and functional dependencies show exactly why.
What this unit covers
Unit 6: Normalisation, Security and Transaction Management
- 1 Update Anomalies and Functional DependenciesWhen one fact is stored in many rows, the table starts to contradict itself, and functional dependencies show exactly why. · 13 min
- 2 Normalisation: First, Second and Third Normal FormsThree tests applied in order, each one removing a kind of repetition, until every fact lives in exactly one place. · 14 min
- 3 Boyce-Codd Normal Form and Properties of DecompositionThe stricter cousin of 3NF, and the two promises every good split of a table must keep. · 12 min
- 4 Database Security and IntegrityKeep the wrong people out, keep the right people within their limits, and keep the data itself honest. · 13 min
- 5 Transaction Management, Concurrency Control and RecoveryHow a bank lets a million people move money at once, survives a power cut mid-transfer, and never loses a naira. · 15 min