On 2/9/2012 4:10 PM, David Salisbury wrote:
>
>
> On 2/9/12 10:08 AM, Rich Shepard wrote:
>> I have reports containing macroinvertebrate collection data for several
>> hundred (or several thousand) of taxa. There is no natural key since
>> there
>> are multiple rows for each site/date pair. Years ago Joe Celko taught
>> me to
>> seek natural keys whenever they might exist. They don't here. That's
>> why I
>> specifically mentioned that in my message.
>
>
> Interesting. I used to think natural keys were okay, but have since decided
> that surrogates are the way to go. That second layer of abstraction allows
> for much easier data modifications when needed. What would be an example
> of a natural key that would be good to use, and why would it be
> preferable??
>
> I'd think the key value must never change, and even say kingdom values in a
> taxa table could possibly change.. might discover something new and do a
> little reordering. :) Also natural keys might be strings, which I'm
> thinking
> would not be as efficient as integers for an index.
>
> -ds
>
Yeah, this is a Vim vs Emacs war. (Vim, :-) )
I prefer surrogates like you. Its way to easy to pick something that
one day has to change.
Within the last year I remember a long thread about this same thing.
-Andy