Re: Sixth normal form

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Mon, 30 Jul 2007 08:27:17 -0300
Message-ID: <46adcae7$0$4022$9a566e8b@news.aliant.net>

Sameeksha wrote:
> Googling out for definition and explanation for sixth normal form only
> resulted in the following information - "6th normal form states that a
> relation R should not contain any non-trivial join dependencies". Also
> everywhere it is stated that this normal form takes into account the
> temporal (time) dimension to the relational model, and that current
> implementations like SQL server 2005 do not implement this normal
> form.
>
> Any more explanation and preferably an example would help in
> understanding the concept behind this normal form.

The join dependency definition is the definition for 5th normal form. 6th normal form was introduced in Date's, Darwen's and Lorentzos' /Temporal Data and the Relational Model/

Basically, 6th normal form puts each non-key attribute in a separate relation. Received on Mon Jul 30 2007 - 06:27:17 CDT