NOT NULL fields in INNODB tables

[Don]

Hi,

My database is composed of INNODB tables such as...
CREATE TABLE user
(
name VARCHAR(255) NOT NULL

) TYPE = INNODB;
The NOT NULL qualifier doesn't work as I would expect. While it
doesn't allow me to do this:

insert user values (null);

It will let me do this:

insert user values ("");

I appreciate that one could argue that "" is different to NULL and
therefore there is nothing wrong with this behaviour. However, surely
there is no defending the following (which is also allowed):

update user set name=NULL;

Is there any way that I can prevent users from setting a field to NULL
or ""?
I am running version 4.0.17-nt on Windows XP

Thanks in advance,
Don