Re: 2NF Controversy
Date: Sat, 29 May 2004 21:31:10 -0700
Message-ID: <34nib0lor6a1mt0cifftqng7j8qk2e27bk_at_4ax.com>
Nomicon <NoSpam_at_hatespam.net> wrote:
>1) One side suggests that in order for a table to violate 2NF, the table
>must have attributes that are dependent on only part of a compound
>PK--this implies that 2NF violations only apply to situations in which a
>table has a compound PK. This requirement has been stated explicitly in
>several definitions.
Yes, that is about it. I note a slight problem in that if a column did not depend on the key at all, to me, the table would not be in 2NF.
>2) The other side suggests that tables violate 2NF when non-key
>attributes apply to multiple rows. This definition also applies to
>tables with simple PK's.
No. It is entirely possible that many records could contain the same value for one column. For example, a mailing list could have 1,000 people living in Vancouver.
>Which defintion is correct? Or are neither correct?
The first.
Sincerely,
Gene Wirchenko
Computerese Irregular Verb Conjugation:
I have preferences. You have biases. He/She has prejudices.Received on Sun May 30 2004 - 06:31:10 CEST