HOPEX Information Architecture > Data Architecture > The data model > Normalization Rules > Third Normal Form
Third Normal Form
 
Rule: An attribute depends directly and uniquely on the entity it describes.
If the “Category Price List” is an attribute of the “Car” entity, this indicates that two cars in the same category can have a different “Category Price List”.
To avoid this, we need to create a “Category” entity that contains the price list.
*This rule is used to reveal concepts that were not found during the first draft of the data diagram.