Re: ALTER TEXT field to VARCHAR(1024)

On Mon, Sep 22, 2014 at 10:31 AM, Merlin Moncure <mmoncure(at)gmail(dot)com> wrote:
> On Fri, Sep 19, 2014 at 7:16 AM, Bill Moran <wmoran(at)potentialtech(dot)com> wrote:
>> On Fri, 19 Sep 2014 09:32:09 +0200
>> Marius Grama <mariusneo(at)gmail(dot)com> wrote:
>>> Can anybody explain me what happens in the background when the alter
>>> statement is executed? I've tried it out on a small copy of the table (70K)
>>> and the operation completed in 0.2 seconds.
>>> Will the table be completely locked during the execution of the ALTER
>>> statement?
>>
>> I share Gavin's concern that you're fixing this in the wrong place. I expect
>> that you'll be better served by configuring the middleware to do the right thing.
>
> I'll pile on here: in almost 20 years of professional database
> development I've never had an actual problem that was solved by
> introducing or shortening a length constraint to text columns except
> in cases where overlong strings violate the data model (like a two
> character state code for example). It's a database equivalent of "C
> programmer's disease". Input checks from untrusted actors should
> happen in the application.
>
> merlin
>

I do not have your experience level with data bases, but if I may, I
will make an addition. Input checks should also happen in the RDBMS
server. I have learned you cannot trust end users _or_ programmers.
Most are good and conscientious. But there are a few who just aren't.
And those few seem to be very prolific in making _subtle_ errors. Had
one person who was really good at replacing every p with a [ and P
with {

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Maranatha! <><
John McKown