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Re: Newbie question

From: Jon Heggland <heggland_at_idi.ntnu.no>
Date: Wed, 22 Jun 2005 08:53:05 +0200
Message-ID: <MPG.1d2329276bc6da749896aa@news.ntnu.no>


In article <42b8475d$0$3144$ed2619ec_at_ptn-nntp-reader01.plus.net>, paul_at_test.com says...
> Jon Heggland wrote:
> >>Moreover, as Joe Celko often points out, any key that is used in the UI
> >>should have check digits or similar to catch data entry errors
> >
> > Why is that? Just to avoid a lookup on the key value?
>
> I guess it's a practical consideration so that simple typos can be
> trapped by the client, to save hitting the database server. In some
> scenarios this could be useful.

It does mean you'll have to maintain consistency between the server-side and client-side checksum algorithms, though. And there is no guarantee you won't be able to enter a non-existing yet valid key (i.e. with correct check digits), is there? And doing the lookup gives the user feedback that s/he actually entered the right key, not just a wellformed  one. But if resources are *really* limited, it could be useful, I guess.

-- 
Jon
Received on Wed Jun 22 2005 - 01:53:05 CDT

Original text of this message

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