Tag: 3NF

A Unified View on Database Normal Forms: From the Boyce-Codd Normal Form to the Second Normal Form (2NF, 3NF, BCNF)

Normal forms for relations is a required topic of a database curriculum. Besides avoiding anomalies, which is already a big issue ¹ , knowing them certainly helps to understand what is going on in your or someone else’s database design. Even if at some point you decide to abandon a normal form, you should know what you are doing and how to pay a price for that.Here, I want to discuss normal forms up to Boyce-Codd Normal Form (that is 2NF, 3NF and BCNF). The reason I want to pack together so many normal forms is that they can be understood better collectively: when you have them packed you can easily see the differences. In some aspects I will follow the approach from a recent book by C. J. Date,