--- In firebird-support@yahoogroups.com, wrote:

> null. However, '' can hardly be considered a value. What's the
> difference between not putting anything in a column, and putting

nothing

What about a column "academic title"? May hold 'PhD' or '' and unknown
is not ''.

But I agree there are a many cases where this distinction is weak.

For my designs I try to use a specific value for null-ness. If domain
analysis confirms, that '' has no distinct meaning from NULL, I
declare the column NOT NULL DEFAULT ''.

For the often used used sex field, I use CHAR(1) NOT NULL DEFAULT '9'
thanks to the wise guys at ISO.

Regards,
Peter Jacobi