Subject Re: [Firebird-general] Suggestion for enhancement
Author Daniel Rail

At July 29, 2004, 11:37, Martijn Tonies wrote:

>> I think that a person should be allowed to remove the NOT NULL flag
>> via ALTER TABLE, since there's no major implication with other record
>> versions. But, also the constraints and dependencies would have to be
>> checked as well. I.e.: If the field is the primary key, then that
>> constraint and corresponding index will have to be dropped first,
>> otherwise the DDL will fail.

> No, instead, it should return an error saying "cannot drop the
> not null constraint from a primary key column" or something.

That's what I'm saying. When I say the DDL will fail, I mean returns
with an error. And, that all the interfering constraints and
dependencies will have to be dropped manually before that DDL
statement to make a field NULLABLE can be executed again.

>> I think that this is 2 separate feature requests, since one is easier
>> to implement than the other.

> From a user POV, I don't see what the problem is?

The problem is not from the users POV, but from a developer's POV and
the time that will have to be spent to implement this. And, I think a
proper consensus would have to be reached on how it should be
implemented, since it requires changes to the ALTER TABLE ALTER COLUMN
statement, that is not defined in the SQL standards, at least up to

Best regards,
Daniel Rail
Senior System Engineer
ACCRA Group Inc. (
ACCRA Med Software Inc. (