Re: Weirdess when altering serial column type

Any further thoughts on this?

Tom Lane wrote:
> Christopher Kings-Lynne <chriskl@familyhealth.com.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