Dmitry Yemanov wrote:

> 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?

Seems good... But didn't we have problem when metadata and data of one
table is changed in one transaction?


Adriano