Database
What is Database Normalization?
Structuring relational tables to eliminate redundant data, so each fact is stored once and updates can't create contradictions.
Definition
Normalization organizes a relational schema so every fact lives in exactly one place. Following the normal forms — 1NF (atomic values), 2NF and 3NF (attributes depend on the whole key and nothing but the key) — a customer's address is stored once in a customers table and referenced by foreign key, never copied into every order row. This prevents update anomalies, where changing data in one place leaves stale copies elsewhere, and shrinks storage. The cost is more joins at query time, which is why read-heavy systems sometimes selectively denormalize after normalizing first.