> They are different. The default for the T_USER domain is a
> server system variable, whereas that for T_DATE is a date literal.

Ok that's true.

But it does not explain for me (as a novice user) why NOT NULL must
be removed from T_USER to work and why T_DATE even works with NOT
NULL.

I looked at all the triggers and found no difference which would
explain it.

Thank's again for your help. Suport seems quite exceptional here.

Regards,
Frank.