Re: Nulls get converted to 0 problem
От | Stephan Szabo |
---|---|
Тема | Re: Nulls get converted to 0 problem |
Дата | |
Msg-id | 20030606062746.J26692-100000@megazone23.bigpanda.com обсуждение исходный текст |
Ответ на | Re: Nulls get converted to 0 problem (Jon Earle <je_pgsql@kronos.honk.org>) |
Список | pgsql-general |
On Thu, 5 Jun 2003, Jon Earle wrote: > 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? Because SQL already defines what NULL means to be something else, it's an unknown value. Also, in C, NULL and "" are different and not very equivalent (try passing strcmp a NULL rather than empty string on many systems ;) )
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