Re: Weirdess when altering serial column type

Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> writes:
> I presume they have to drop the default, then drop the sequence to get
> rid of it.

Hmm. Right at the moment I don't think you *can* get rid of it, short
of dropping the column altogether.

regression=# create table z(f1 serial);
NOTICE: CREATE TABLE will create implicit sequence "z_f1_seq" for serial column "z.f1"
CREATE TABLE
regression=# drop sequence z_f1_seq;
ERROR: cannot drop sequence z_f1_seq because table z column f1 requires it
HINT: You may drop table z column f1 instead.
regression=# alter table z alter f1 drop default;
ALTER TABLE
regression=# drop sequence z_f1_seq;
ERROR: cannot drop sequence z_f1_seq because table z column f1 requires it
HINT: You may drop table z column f1 instead.

Possibly it would be better if the implicit dependency led from the
sequence to the column default rather than directly to the column ...
but I'm too tired to think of the possible consequences. I think we
may have considered and rejected that idea ...

regards, tom lane