Can you explain the different forms of database normalization?

Database normalization is the process of organizing data to reduce redundancy and improve integrity. The main normal forms are:

1. First Normal Form (1NF) — all fields contain atomic values, with no repeating groups or arrays.

2. Second Normal Form (2NF) — the table is in 1NF, and all non-key fields depend fully on the entire composite key (if the key is composite).

3. Third Normal Form (3NF) — the table is in 2NF, and there are no transitive dependencies between non-key fields (i.e., non-key fields do not depend on each other).

4. Boyce-Codd Normal Form (BCNF) — a strengthening of 3NF, where for every functional dependency, the determining attribute is a key.

Example: if there is a table with order data, which also stores customer information, normalization involves splitting into an orders table and a customers table to avoid duplicating customer data in each order.