Re: 1st and 2nd NF

From: Larry Coon <lcnospam_at_assist.org>
Date: Fri, 05 Dec 2003 11:46:32 -0800
Message-ID: <3FD0E098.2D19@assist.org>

Ryan Gaffuri wrote:

> I have a college textbook and it discuss 3-6 NF and BCNF, but totally
> skips 1NF and 2NF. can someone help me in understanding this? I dont
> need it for school, I just want to know what it is.

If I remember right, it was the Silberschatz textbook that did that.

In simple terms, 1NF simply says "scalar values only." At the intersection of a row and column, you will find only atomic values.

2NF means: 1) It is in 1NF, and 2) There are no FDs where a part of (not the entire) candidate key is the determinant. This only really matters for composite keys. IE, if (a,b) are a composite candidate key, there can be no FDs of the form a-->x or b-->x.

Larry Coon
University of California Received on Fri Dec 05 2003 - 13:46:32 CST