Re: NULL versus NOT NULL usage

Another point worth mention in PowerBuilder is that a NULL returned from a datawindow when loading into
a string or int array variable causes a datatype mismatch. NULLS dont have a datatype in class attribute terms!

Consequently, if you concatenate in Sybase one NULL and one NOT NULL field, it will also return a NULL!

This is all very disturbing!

Thomas Kellerer <Thomas.Kellerer_at_say_no_to_spam_tps-labs.de> wrote in article <35756519.783767CA_at_say_no_to_spam_tps-labs.de>...
> >>If you need to maintain a distinction between nothing
> >>and a 0-length string, blank or zero, then your column
> >>should be null.
>
> But only if you are not using Oracle. An empty string is always stored as
 a null
> string when using the varchar datatype...
>
> >>Many client developers have an innate fear of null.
> >>The practical use of the null set is foreign
> >>to many of them. However, the client developers must
> >>learn the null set.
>
> But there are development environments which incorporate the NULL
 concept. In
> PowerBuilder each and every variable can be NULL (which does create some
> problems, escpecially with string concatenation, because NULL + something
 =
> NULL). PB provides to functions SetNull() and IsNull() to handle that...
>
> Thomas
>
> ==========================================================
> Who is user GENERAL FAILURE and why is he reading my disk?
>
>
>
Received on Thu Jun 04 1998 - 00:00:00 CEST