Re: Artificial Primary keys
From: Bernard Peek <bap_at_shrdlu.com>
Date: Wed, 30 Jan 2002 12:48:51 +0000
Message-ID: <EfHws0Dzu+V8EwB8_at_shrdlu.com>
Date: Wed, 30 Jan 2002 12:48:51 +0000
Message-ID: <EfHws0Dzu+V8EwB8_at_shrdlu.com>
In message <a35l0g$a5k$1_at_news.net.uni-c.dk>, Jan Emil Larsen <jel_at_g-it.dk> writes
>> Correct. It stems from the definition of a key.
>A (primary) key is a (combination of) attribute(s) that uniquely identifies
>an object (or a row in an RDB).
The dependency works both ways. The value of the key is dependent on the object. If the object does not change then the key should also be unchanging. I am excluding the pathological condition where the data has been recorded incorrectly.
-- Bernard Peek bap_at_shrdlu.com In search of cognoscentiReceived on Wed Jan 30 2002 - 13:48:51 CET