Question

I tried to consolidate everything I learned about normalization in this blog post
http://geekyisawesome.blogspot.com/2011/03/database-normalization-1-2-3-nf.html
but I need to make sure that I understood everything correctly. Could you notify me of any mistakes?

Thanks

Answer 1

I wouldn’t say there are any mistakes. The examples are sound. I like the fact that you showed a couple of different ways of doing 1NF.

I would say that the post is a little bit confusing. Perhaps you might consider laying out a precise statement of what each NF is as you get to it and include a short description of what the attending anomalies are for 1NF and 2NF. That way, when you go through your sample relations, it will be clearer what the problems are and why the next NF is a solution rather than just another way of doing it. I found the transitions from one NF to the next weren’t crystal clear. A neophyte would benefit more from clearer distinctions between each NF, since it can be hard to keep straight in your head at first, as you pointed out in your introduction.

I like how 3NF can be summed up in the old addage: “The key, the whole key, and nothing but the key, so help me Codd.” This is very succinct and highlights all of the important attributes of a relation in 3NF. Each attribute must depend on the key (1NF) the whole key (2NF) and nothing but the key (3NF). This is useless for explaining normalization but it’s a great way to remember it once you’ve learned it.