Database Design and Relational Theory: Normal Forms and All That Jazz

© C. J. Date 2019

C. J. DateDatabase Design and Relational Theoryhttps://doi.org/10.1007/978-1-4842-5540-7_14

14. 6NF

C. J. Date¹ 

(1)

Healdsburg, California, USA

 

Why, sometimes I’ve believedas many as six impossible things before breakfast.

—Lewis Carroll: Alice’s Adventures in Wonderland (1865)

To paraphrase something I said in Chapter 9, I’ve assumed throughout this book so far that the only normal forms we care about are ones that involve projection as the decomposition operator and join as the corresponding recomposition operator. I also said in that same chapter that, given that assumption, it followed that 5NF was the final normal form. However, I did also say in a footnote to that chapter that there was something called sixth normal form or ...