Re: Advanced SQL
Date: Fri, 07 Sep 2007 15:43:26 +0200
Message-ID: <fbrki3$837$1_at_orkan.itea.ntnu.no>
Quoth Evan Keel:
> "David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in message
> news:pZSdnfih_oRy5H3bRVnyigA_at_giganews.com...
>> Call me picky but I am not entirely comfortable with that U.Texas site,
>> even though it's a commendable effort overall.
>>
>> "The definition of second normal form states that only tables with
>> composite primary keys can be in 1NF but not in 2NF"
>
> They have it right here. All non-key attributes must be dependent on the
> full key. Only applies to tables with keys composed of multiple columns>
No. There may be dependencies where the left side is empty. But it's a common mistake. If I remember correctly, one of my database textbooks "proves" that any relvar with just two attributes is automatically in BCNF.
-- JonReceived on Fri Sep 07 2007 - 15:43:26 CEST