Re: Nulls get converted to 0 problem

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От terry@greatgulfhomes.com
Тема Re: Nulls get converted to 0 problem
Дата
Msg-id 002401c32c1e$c32c3080$2766f30a@development.greatgulfhomes.com
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Ответ на Re: Nulls get converted to 0 problem  (Jon Earle <je_pgsql@kronos.honk.org>)
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One good reason not interpret the empty string as NULL is because the empty
string could violate a foreign key constraint, whereas a NULL says "don't
evaluate the fkey constraint, there is no value here for this row"

Terry Fielder
Manager Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com
Fax: (416) 441-9085


> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Jon Earle
> Sent: Thursday, June 05, 2003 9:39 AM
> To: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Nulls get converted to 0 problem
>
>
> On Wed, 4 Jun 2003 terry@ashtonwoodshomes.com wrote:
>
> > Oracle *incorrectly* interprets blank (empty) strings as
> NULL.  They are NOT
> > the same.  A string of zero characters is a string
> nonetheless.  A NULL is
> > "the absence of value", which equals nothing (theoretically
> not even another
> > NULL).
>
> If you're testing a value, you're testing to see if there's
> something in
> there or not - what difference does it make if the variable
> contains 0, ""
> or NULL?
>
> Why not adhere to the practices inherent (and thus anticipated by
> developers) in other languages (C comes to mind) where 0,
> NULL and "" are
> equivalent?
>
> Cheers!
>
> --
> Jon Earle
>
> SAVE FARSCAPE http://www.savefarscape.com/
>
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