SQL
First, Second and Third Normal Form
Normalisation worked through on one table: remove repeating groups, then partial dependencies, then transitive ones - with the SQL at each step.
Normalisation
1NF to BCNF, functional dependencies, anomalies and denormalisation.
3 notes
Notes
SQL
BCNF and Functional Dependencies
The formal notation behind normalisation, and the stricter normal form that catches what 3NF allows through when candidate keys overlap.
SQL
Anomalies and Denormalisation
The three anomalies normalisation prevents, and the disciplined way to reintroduce redundancy when reads genuinely demand it.