Each attribute contains only 1 atomic value, and that value is only a single value from that domain
- eg, don't have repeated columns: SaleID, Product1ID, Qty1, Product2ID, Qty2, etc..
- eg, don't have multiple values in the same column and same row: SaleID, ProductID, having multiple, possibly comma-separated, values for ProductID suggesting multiple products were sold
- must be 1NF AND...
- Every non-prime attribute must depend on entire candidate key of the table, or another prime attribute. See this example where Current Work location is only dependent on Employee while the candidate key is comprised of Employee AND Skill
- In other words, each attribute is Fully Functionally Dependent on the Key
- must be 2NF AND...
- Every non-prime attribute must NOT be transitively dependent on every super key (ie, must be directly dependent)
- must be 3NF AND...
- Any determinant attribute can be used as the row's ID field