[AccessD] On DB Bloat, Bad DB Design, and various

Your decision isn't based on a business rule either. The 255 limit is because you don't want to program around a memo.

Your right that this discussion is silly, because 10 e-mails ago I had already decided when to use the 255 method and when not.

Scott Marcus
TSS Technologies, Inc.
marcus at tsstech.com
(513) 772-7000

 -----Original Message-----
From: 	accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com]  On Behalf Of John W. Colby
Sent:	Tuesday, May 25, 2004 2:29 PM
To:	Access Developers discussion and problem solving
Subject:	RE: [AccessD] On DB Bloat, Bad DB Design, and various

>But you are arbitrarily limiting them. In this case to 255.

Not true, arbitrary implies flipping a coin and taking whatever comes down.
I am in no way doing that.  I am making an informed choice between two data
types.  Memos have many problems that I don't want to deal with if I don't
have to.  If I had the choice of using a 4K text field I would (probably).

Here is the (original) argument (as I read it)

"I want to be able to display all of the data that the user is able to
enter.  So if I can only display 20 characters I limit the user to 20
characters."

Now tell me, is that a valid reason to set a limit to a field size?  Not in
my book.  If he can only display 10 characters for the last name he sets the
text field to 10?  If only 5 then he sets it to 5?  Whose data is this
anyway?

This whole argument is simply silly.  You are choosing some number, out of
thin air, no validation testing, no mathematical proof that the size you are
setting is 99.9% of all the instances the user wishes to enter.  Just a
number, grabbed out of thin air, that is what YOU decide the data should fit
in.  Flip a coin, pull a number out of a hat, spin a roulette wheel.

I am making a decision between 2 choices, a data type of 255 characters or a
data type of 32K.  I then look at the expected data and if there is a
reasonable use for the memo I use it.

Your choices are 1,2,3,4,5,6,7,8,...255 characters.  But there is no
specific reason for 2 instead of 3, or 4 instead of 6, just "what you think
"should" work".

Pick one at random (and attempt to validate your reasons so that you are
comfortable) then run around expanding the number when it is not a good
choice.

I personally don't care if you do that but to tell me that I am using bad
programming practices because I don't make such capricious and arbitrary
decisions is a bit of an insult wouldn't you say?

And FINALLY, notice that you are studiously avoiding any talk of business
analysis.  I have stated over and over that if there is a BUSINESS reason
for limiting a field length then I would do so.  "My address fields are
limited to 25 characters" is NOT a business rule.  "I limit the field to the
size I can display" is CERTAINLY not a business rule.

John W. Colby
www.ColbyConsulting.com

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Scott Marcus
Sent: Tuesday, May 25, 2004 1:38 PM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] On DB Bloat, Bad DB Design, and various


But you are arbitrarily limiting them. In this case to 255. So I'm back to
saying you should set it to memo if you really feel this way.

Scott Marcus
TSS Technologies, Inc.
marcus at tsstech.com
(513) 772-7000


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