Re: Bug of ALTER TABLE DROP CONSTRAINT

> Considering the following sequence:
>    create table t(a int primary key);
>    alter table t drop constraint t_pkey;
>    insert into t values(null);
>    ERROR:  null value in column "a" violates not-null constraint
>
> My question is, why "null" is not allowed to be inserted after primary key
> constraint has been dropped.

Making a column into the primary key forces the column to NOT NULL.
You'll need to DROP NOT NULL separately.

It's probably possible to beat on the code hard enough to fix this,

but I'm not really sure there's much point, since the situation is
rare and the workaround is easy.