Re: Violation of NOT NULL

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Wm. G. Urquhart
> Sent: Thursday, May 23, 2002 11:19 AM
> To: Mike Mascari
> Cc: PostgreSQL General Forum
> Subject: Re: [GENERAL] Violation of NOT NULL
>
>
> On Thu, 23 May 2002, Mike Mascari wrote:
>
> <snip/>
> > Also, if by chance you are coming over from Oracle and expect an empty
> > string to be treated as NULL, it is not...
> >
> > Mike Mascari
> > mascarm@mascari.com
> >
>
> Well I have a few years of Oracle behind me and it has to said I was
> working on that assumption.
>
> With that said if '' does != NULL then what does? Just NULL? In my book
> NULL means undefined and IMHO you can't get more undefined than ''!

NULL is unknown. '' is empty. If I don't have a middle name, then my middle
name = ''. If I might have one, but you don't know what it is, then my
middle name IS NULL. (Which is, subtly, not the same thing as = NULL, as
NULL is a state or condition, rather than a value. Nothing is = NULL, not
even NULL itself.)

- J.

Joel BURTON | joel@joelburton.com | joelburton.com | aim: wjoelburton
Knowledge Management & Technology Consultant