Eliminate partial dependencies on a composite primary key.
Second Normal Form (2NF) is the next step in the normalization process and addresses a specific type of redundancy that can occur in tables with composite primary keys. A table is in 2NF if it meets two conditions: first, it must already be in 1NF. Second, every non-primary-key attribute in the table must be fully functionally dependent on the entire composite primary key. This means that a non-key attribute cannot depend on only a part of the composite key. This issue, called a 'partial dependency', only arises when a table has a composite primary key (a primary key made up of two or more columns). For example, consider a table `Order_Items` with a composite primary key of (`order_id`, `product_id`). Let's say it has columns `quantity` and `product_name`. Here, `quantity` depends on both `order_id` and `product_id` (it's the quantity of a specific product in a specific order), so it is fully dependent. However, `product_name` depends only on `product_id`. This is a partial dependency. It causes redundancy because the same product name will be repeated for every order that includes that product. To achieve 2NF, we would decompose the table. We would keep `Order_Items` with (`order_id`, `product_id`, `quantity`) and create a new `Products` table with (`product_id`, `product_name`). This eliminates the partial dependency and the associated redundancy.