Re: postgresql vs mysql - Mailing list pgsql-general

From brian
Subject Re: postgresql vs mysql
Date
Msg-id 45DD276F.5040909@zijn-digital.com
Whole thread Raw
In response to Re: postgresql vs mysql  (Chris <dmagick@gmail.com>)
List pgsql-general
Chris wrote:
>
> It's not an oddity.
>
> An empty string is a KNOWN value. You know exactly what that value is -
> it's an empty string.
>
> A NULL is UNKNOWN - it doesn't have a value at all.
>

Just to expand on that (and to drag this thread out a little longer), i
find that a pretty good way to get across this difference is to refer to
it as *the* empty string. I prefer this description because it is
implicit that it is still a string. NULL has no type, regardless of the
column it is inserted into. Thus, the empty string is NOT NULL.

brian

pgsql-general by date:

Previous
From: "John Smith"
Date:
Subject: Re: postgresql vs mysql
Next
From: "sangeetha k.s"
Date:
Subject: what compression is used in on disk bitmap index implementation