Re: VARCHAR2: NULL value vs. empty string

From: Daniel Gustafsson <daniel_at_mimer.se>
Date: 13 Dec 2003 01:46:11 -0800
Message-ID: <de4cfd03.0312130146.1b3877d0@posting.google.com>

Daniel Morgan <damorgan_at_x.washington.edu> wrote in message news:<1071251255.44416_at_yasure>...
> NoName wrote:
>
> Because the ANSI standard allows vendors the ability to implement the
> standard any way they wish. Oracle chose one way, others chose another way.

That is wrong.

> Do keep in mind that Oracle has been around a very long time. And many
> of Oracle's design decisions were made before there was an ANSI standard
> for databases. So as long as Oracle's implementation met the standard
> there was no reason to change.

It does not meet the standard in this matter, and Oracle also say that they don't follow the standard.

From the standard compliance tables in the Oracle SQL Reference manual.
"Oracle partially supports these subfeatures:

E021-02, CHARACTER VARYING data type (Oracle does not distinguish a
zero-length VARCHAR string from NULL)
E021-03, Character literals (Oracle regards the zero-length literal ''

as being null)"

This is also a quote from the Oracle SQL Reference manual about NULLs. "(Oracle currently treats a character value with a length of zero as null. However, this may not continue to be true in future releases, and Oracle recommends that you do not treat empty strings the same as nulls.)"

Regards
Daniel Gustafsson, Mimer SQL Development http://www.mimer.se Received on Sat Dec 13 2003 - 03:46:11 CST