Database Normal Forms Every Developer Should Know

Normalization aims to eliminate redundancy and enforce data integrity by organizing data into logical, dependency-driven forms.

1. First Normal Form (1NF): Removes repeating groups and ensures atomic values in each column.
2. Second Normal Form (2NF): Removes partial dependencies by ensuring all non-key columns depend on the full primary key.
3. Third Normal Form (3NF): Eliminates transitive dependencies, ensuring non-key columns depend only on primary keys.
4. Boyce-Codd Normal Form (BCNF): Strengthens 3NF by removing anomalies that exist due to overlapping candidate keys. If one column depends on some other column, then that “other column” must be enough to identify each row uniquely.
5. Fourth Normal Form (4NF): Ensures that a table does not mix multiple independent one-to-many relationships for the same entity.