Adriano,

> The syntax would be:
> alter table <table> alter <field> not null;
> alter table <table> alter <field> null;
>
> It's semantics would be:
> When putting "NOT NULL", in DFW (commit time) the table is locked
> and a BLR dynamic query is constructed to inspect for NULL values. If
> there are, we throw an error.

As a partially related question, what about adding a column with a NOT
NULL constraint without de-facto violating that constraint, as now?

IIRC, there was a suggestion to use a DEFAULT value (if defined) to
populate such a column and reject the operation otherwise. I'm not sure
it follows the standard though.

Do you think it could be a good idea? Could you suggest anything else?


Dmitry