What is it
Normalisation is the process of organising a relational database's tables to reduce data redundancy and prevent update anomalies, following a series of formal rules called normal forms (1NF, 2NF, 3NF, and beyond).
Why it matters
Proper normalisation prevents the same piece of data from being stored in multiple places, which would otherwise let different copies of the same fact drift out of sync — a subtle but serious data integrity problem that normalisation directly prevents.
Exam tip
Learn to recognise the specific problem each normal form solves (1NF removes repeating groups, 2NF removes partial dependencies, 3NF removes transitive dependencies) rather than just memorising the rules — understanding the 'why' makes it far easier to spot normalisation violations in an unfamiliar schema.
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