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

Scott Marcus marcus at tsstech.com
Mon May 24 13:09:56 CDT 2004


I know that I jumping in the middle but...

By setting the field to 255 aren't you still imposing a limit. Why not set it to memo to be safe? (playing devils advocate) I know there are reasons not to set to memo and I'm not suggesting you do so. I'm just pointing out that maybe you setting it to 255 is going to get you burned in another way down the road. Don't ask me what other way because your reasoning for setting it to 255 is for things unforeseen. I understand where you are coming from. Like Brett I'm just surprised hearing that you do set it to 255.

Not arguing (maybe I'll start setting mine to 255), just thinking of the flip side. 

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 DWUTKA at marlow.com
Sent:	Monday, May 24, 2004 1:45 PM
To:	accessd at databaseadvisors.com
Subject:	RE: [AccessD] On DB Bloat, Bad DB Design, and various

Good questions.

First of all, if a user needs 255 characters, isn't it our job to provide
that to them?  In my previous 'state abbreviation' example, the 'need' for
setting a two character limit is non-existant, it should be done in the FE,
not in the BE design.  We are all kind of harping on 'set' fields, where a
limit is usually a pretty well educated guess, or even an established fact,
barring no future changes.  Let me give you a different (real life) example.
I wrote an ASP version of a paper form.  The original developer (who I was
actually working for) had some unusual quirks in his system, too many to get
into with email.  However, to handle certain issues, I had to 'ignore' a lot
of errors.  Not really a problem, unless of course the errors are telling
you that data isn't being written for one reason or another.  The system
started as an Access BE, but was later converted to SQL Server, with all of
the 'limitations' that were built into the Access BE.  One such limitation
was a field 'Exact Location where accident occurred'.  This field was set to
a 35 character max.  Because of the forced errorhandling, some people
weren't getting that field's data saved, because they were putting in more
then 35 characters.

Quite frankly, the database I was 'using' should have been completely
redesigned.  It is something the original developer and I have talked about
many times.  So the 35 character limit is just a drop in the bucket.
However, if that limit wasn't set, then an issue would have never arisen
about it.

I'll be honest with you, I don't write a heck of a lot of Access reports.  A
large majority of my FE stuff (including reports) is done in ASP.  However,
when I do use Access, I size the report fields so that they display what
would be normal data.  You can always set the 'Can grow' property.  Besides,
I would personally rather get called to change the size of a report's field,
then get told that they cannot entire data into my database.

I'm pretty sure I haven't said that setting field size limits is wrong.  If
I did, sorry, it's not wrong, I've just been burned many times on the issue.
But then again, I've been burned on all sorts of other things, which just
didn't work when circumstances changed.  I have yet to be burned with
setting the fields to their max size.

Several people have brought up very valid reasons as to why they use
different max field sizes.  Your point about report fields is certainly a
valid argument.  However, I haven't had to work on anything from people on
this list (with the exception of Mike Mattys, and I have absolutely no
complaints there!).  In the cases where I have been burned by previous
developers setting field limits, I would be willing to bet a round of beers,
that 9 out of 10 times, the limits were set due to the myth that setting the
field size smaller decreases the size of your database.

So if you set a limit, and you have a valid reason to do so, more power to
you!  Seriously.  I am just griping on where I have been burned, and trust
me, not a single 'limit' that has burned me was set for the reasons brought
up so far!

Drew

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Brett Barabash
Sent: Monday, May 24, 2004 12:22 PM
To: 'Access Developers discussion and problem solving'
Subject: RE: [AccessD] On DB Bloat, Bad DB Design, and various


I've been watching this thread for a while now, and need to ask this
question to Drew and JC:

If you always allow 255 characters for your text fields, do you format your
forms and reports to display that size of data?

Drew, you talk about being "burned by these limitations".  It would seem to
me that if your report's fields are not wide enough and truncate the field
contents, you have effectively imposed that limitation.  However, you have
done it in a much more insidious way, by allowing the user to type in a long
string and then not displaying its full contents in the output.  This
seriously breaks one of my cardinal design rules of accepting user input
that the system is not able to process.

Of course, I'm assuming that you don't display all 255 characters.  If my
assumption is wrong and you actually do leave enough room for all 255,
doesn't this result in pretty weird looking tabular reports?  How many 255
character fields can you fit across an 8 1/2 X 11" piece of paper?  1?  2
perhaps?

Have you ever encountered users that misuse the fields?  I have (in almost
every company I've worked for).  Doesn't allowing the entry of 255
characters in any text field (say Address 2) invite the careless user to
treat it as the Memo field they forgot to ask for?

Seems like sloppy programming to me.  And very surprising comments from
developers who preach about following good data modeling practices.


-----Original Message-----
From: DWUTKA at marlow.com [mailto:DWUTKA at marlow.com] 
Sent: Friday, May 21, 2004 1:54 PM
To: accessd at databaseadvisors.com
Subject: RE: [AccessD] On DB Bloat, Bad DB Design, and various


I think we are talking apples and oranges here.  Yes, the page file size
needs to be taken into consideration.  I set all of my text fields to 255. I
do this because I don't want to be backed into a wall, because I set a size
limit that prevents a user from entering what they need to enter.  If I
provide a phone number field, and set it to 10 (area code and phone number),
sure, I am 'limiting' the client.  However, what happens when they want to
put in an international number.  Or if the US decides to move to 8 digit
phone numbers.  Who knows, there are all sorts of reasons that the field
size may change.  Now, if I have some sort of logic checking data integrity,
that would have to be changed, but if I don't, by having the field size set
to 10, I am limiting the users at the table level, to a point where they
cannot do their job.  If I have it set to 255, I am 99.99999% they would
never put 255 characters into that field, but they may put in 11, or 12,
etc.  

Oh well, this really isnt' something I feel like arguing about.  I see your
point Jürgen, but this is really a case of who has been burned and how.  I
have been burned over and over by previous developers putting such
limitations into their databases.  I have never been burned by the page file
size.  In fact, I completely forgot that the limit even existed, until it
popped up on the list a few weeks ago.  So that is why I set my default text
field size to 255.

Drew


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