Normalization

Normalization is the process of organizing tables to reduce redundancy and prevent update anomalies, usually by splitting data into related tables. The common targets are 1NF, 2NF, and 3NF.

1NF requires atomic values (no lists in a cell) and a primary key. 2NF removes partial dependencies on a composite key. 3NF removes transitive dependencies, where a non-key column depends on another non-key column.

Normalization keeps each fact in exactly one place, so updates can't leave contradictory copies. Analytical and reporting databases sometimes denormalize deliberately, trading redundancy for fewer joins and faster reads.