Re: Normalization and Derived Information
From: Kenneth Downs <firstinit.lastname_at_lastnameplusfam.net>
Date: Thu, 23 Sep 2004 10:32:28 -0400
Message-ID: <spmuic.rc9.ln_at_mercury.downsfam.net>
>> The howls of protest begin,
>> "that's not normalized!" If this is a normalization violation, I cannot
>> figure out what form I've violated because there is no table where I can
>> put this, it is dependent upon non-key variables within the table, but
>> belongs to the table.
Date: Thu, 23 Sep 2004 10:32:28 -0400
Message-ID: <spmuic.rc9.ln_at_mercury.downsfam.net>
Larry Coon wrote:
> Kenneth Downs wrote: >>>
>> Order # Qty Item Price
>> ========= ==== ======== =========
>> 1000-23 5 XJ7 75000
>> 1000-23 5 ES300 42500
>> 1001-95 1 BUGWHIP 2
>> 1001-95 3 FEEDBUCK 10
>
>> The howls of protest begin,
>> "that's not normalized!" If this is a normalization violation, I cannot
>> figure out what form I've violated because there is no table where I can
>> put this, it is dependent upon non-key variables within the table, but
>> belongs to the table.
> > Third normal form. If there exists functional dependencies > of the form A-->B where A and B are non-key attributes, then > your table is not in 3NF. Here you would have a dependency > of the form (Qty, Price) --> ExtendedPrice. >
A clear and simple explanation always makes me think I should have figured it out myself. Thank you.
-- Kenneth Downs Use first initial plus last name at last name plus literal "fam.net" to email meReceived on Thu Sep 23 2004 - 16:32:28 CEST