[AccessD] Re: Using Dates

Charlotte,

What I think he is saying is that in 99% of the cases, the regular date 
dimension table will work.  In a few cases, where the date may be missing 
and you want to get some kind of value for it, you cannot use the date 
itself as the key, thus the surrogate.  The surrogate would be stored in 
the fact tables (another data warehousing concept, for those that do not 
know about them).  That way when you hit an invalid or null date value, the 
date dimension table would be able to handle it in a predefined way.

Robert

At 03:46 AM 2/3/2004 -0600, you wrote:
>Date: Mon, 2 Feb 2004 12:29:49 -0800
>From: "Charlotte Foust" <cfoust at infostatsystems.com>
>Subject: RE: [AccessD] RE: Using Dates
>To: "Access Developers discussion and problem solving"
>         <accessd at databaseadvisors.com>
>Message-ID:
>         <E61FC1D4B1918244905B113C680BEA8632C448 at infoserver01.infostat.local>
>Content-Type: text/plain;       charset="us-ascii"
>
>I'm not even sure what Ralph is saying there, and it flies in the face
>of what he does in some of his books, so I have no answer for you, John.
>Keep in mind, though, that datawarehouses are indexed somewhat
>differently from transactional databases, so that may be where the
>confusion is coming in.  If you were using surrogate keys and
>meaningless values as the PK, the dates in the main records would need
>to be inserted *from* the date table, and that isn't generally the way
>the thing is used.
>
>Charlotte Foust