Re: Identity columns should own only one sequence

On Fri, May 03, 2019 at 08:14:35AM +0200, Laurenz Albe wrote:
> On Thu, 2019-05-02 at 22:43 +0200, Peter Eisentraut wrote:
>> I think the proper way to address this would be to create some kind of
>> dependency between the sequence and the default.
>
> That is certainly true. But that's hard to retrofit into existing databases,
> so it would probably be a modification that is not backpatchable.

And this is basically already the dependency which exists between the
sequence and the relation created with the serial column. So what's
the advantage of adding more dependencies if we already have what we
need? I still think that we should be more careful to drop the
dependency between the sequence and the relation's column if dropping
the default using it. If a DDL defines first a sequence, and then a
default expression using nextval() on a column, then no serial-related
dependency exist.
--
Michael