Second normal form

Learn second normal form (2NF).

2NF

2NF is in 1NF with no partial dependency. In a composite key, each column must depend on the whole key.

-- order_items(order_id, product, qty, product_name)
-- product_name yalnız product'a bağlı → 2NF ihlali

Move product_name to a products table.

2NF removes partial dependencies. A column depending on part of a composite key is moved to its own table.

For example, in a table keyed by (order_id, product_id), the product name depends only on product_id, so it moves to the products table.

Move product_name to a products table to reach 2NF.

Show example solution

CREATE TABLE products (
  id INT PRIMARY KEY,
  name VARCHAR(100)
)

2NF dependency

2NF: depends on the ____ as a whole

Show answer

2NF: depends on the key as a whole