Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com> writes:
> I have created a table with primary key, and then dropped primary key from
> table. But table still have not null constraint added by primary key.
> Is there any other statement to delete primary key with not null?
> or this is an expected behaviour of pg?
Yes, it's expected. You can use "alter table t alter column c drop not
null" if you don't want the not-null constraint anymore.
regards, tom lane