Understanding the Normalization Example

Unnormalized Order Table

Contains Order Number, Customer Number, Customer Name, Customer Address, Product Number, Product Name, Quantity, Product Price, and Order Date, with repeating product information.

First Step of Normalization (1NF)

Separate the repeating product information into individual line items.

Order Table After 1NF

Contains Order Number, Customer Number, Customer Name, Customer Address, and Order Date.

Line Item Table After 1NF

Contains Order Number, Product Number, Product Name, Quantity, and Product Price.

Second Step of Normalization (2NF)

Move fields that depend only on part of the composite key into their own table.

Line Item Table After 2NF

Contains Order Number, Product Number, and Quantity.

Product Table After 2NF

Contains Product Number, Product Name, and Product Price.

Third Step of Normalization (3NF)

Move fields that depend on another non-key field into a separate table.

Order Table After 3NF

Contains Order Number, Customer Number, and Order Date.

Customer Table After 3NF

Contains Customer Number, Customer Name, and Customer Address.