Re: Anybody for Automated Comparative Normal Form?
From: Kenneth Downs <firstinit.lastname_at_lastnameplusfam.net>
Date: Fri, 19 Nov 2004 19:11:40 -0500
Message-ID: <sme272-02v.ln1_at_pluto.downsfam.net>
>>
>> A choice quote is this by Date, in describing the original definition of
>> DK/NF:
>>
>> "Fagin defines a relvar R to be in DK/NF if and only if every constraint
>> on R is a logical consequence of what he (Fagin) calls the domain
>> constraints and key constraints on R."
>>
>> Perhaps we can rephrase this into the vernacular as saying all biz rules
>> are specified completely by primary and foreign keys?
Date: Fri, 19 Nov 2004 19:11:40 -0500
Message-ID: <sme272-02v.ln1_at_pluto.downsfam.net>
Jan Hidders wrote:
> Kenneth Downs wrote:
>>
>> A choice quote is this by Date, in describing the original definition of
>> DK/NF:
>>
>> "Fagin defines a relvar R to be in DK/NF if and only if every constraint
>> on R is a logical consequence of what he (Fagin) calls the domain
>> constraints and key constraints on R."
>>
>> Perhaps we can rephrase this into the vernacular as saying all biz rules
>> are specified completely by primary and foreign keys?
> > Careful, careful. Fagin is talking only about candidates keys, which is > more than primary keys and does not include foreign keys. > > -- Jan Hidders
Your caution is appreciated. In my enthusiasm for the similarities, I probably did not take enough care to enumerate the differences. The idea was to take DK/NF as a starting point for conversation but to rapidly depart into other areas.
-- Kenneth Downs <?php echo "sig block. cool."; ?>Received on Sat Nov 20 2004 - 01:11:40 CET