Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> comp.databases.theory -> Re: date as a foreign key

Re: date as a foreign key

From: Mikito Harakiri <nospam_at_newsranger.com>
Date: Mon, 24 Sep 2001 17:24:34 GMT
Message-ID: <m%Jr7.3243$ev2.3228@www.newsranger.com>


In article <8eIr7.64$h4.2891_at_petpeeve.ziplink.net>, David Cressey says...
>
>Just a general comment on the use of timestamps. This comment may or may
>not apply to the originator of this thread.
>
>Real Numbers (floating point numbers) are a poor choice for indexes, and
>therefore a poor choice for primary keys.
>Although Oracle timestamps are not real numbers, they suffer from the same
>problem somewhat. The problem is that we tend to treat "equality" of two
>measurements as being a somewhat fuzzy concept. If the difference between
>two measurements is less than some suitably small value, epsilon, we say
>"close enough" and regard them as equal.

Therefore, you insist upon a discrete domain for foreign key constraints only? Then, strings would probably be a poor choice as well, because the difference between the 2 could be "infinetely" small. Take "David Cressey" and "Dave Cressey", for example, isn't it pretty much much the same as 1.00000 and 1.00001? Again, from one perspective surrogate keys are bad, while from the referential integrity standpoint we need to use them. Received on Mon Sep 24 2001 - 12:24:34 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US