On Sun, 4 Apr 2010 19:36:01 -0700, RChamp1969
<(E-Mail Removed)> wrote:
>I am struggling with Access 2007, trying to teach myself how to build an
>expression in a table. My table is a listing of customers, names, address,
>the last field I want to put in is "Preferred_Customer", I want this to look
>at the "YTD_Orders" and see if it is >= 10000, if so then Yes if not No.
Storing derived data such as this in your table accomplishes
three things: it wastes disk space; it wastes time (almost
any calculation will be MUCH faster than a disk fetch); and
most importantly, it risks data corruption. If one of the
underlying fields is subsequently edited, you will have data
in your table WHICH IS WRONG, and no automatic way to detect
that fact. For instance, you could have a customer with 9950 YTD
orders; if they order 200 more, their status should change.... but
if the table is already populated it won't.
Just use a *QUERY* based on the table, to count or sum values in YTD_Orders,
and dynamically assign the value accordingly:
IIF(YTD_Orders >= 10000, "Preferred Customer", Null")
--
John W. Vinson [MVP]
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