Re: Review: Non-inheritable check constraints

> rhaas=# create table A(ff1 int);
>> CREATE TABLE
>> rhaas=# create table B () inherits (A);
>> CREATE TABLE
>> rhaas=# create table C () inherits (B);
>> CREATE TABLE
>> rhaas=# alter table only b add constraint chk check (ff1 > 0);
>> ALTER TABLE
>> rhaas=# alter table a add constraint chk check (ff1 > 0);
>> NOTICE: merging constraint "chk" with inherited definition
>> ALTER TABLE
>>
>> At this point, you'll find that a has a constraint, and b has a
>> constraint, but *c does not have a constraint*. That's bad, because
>> a's constraint wasn't "only" and should therefore have propagated all
>> the way down the tree.
>>
>>
> Apologies, I did not check this particular scenario.
>
> I guess, here, we should not allow merging of the inherited constraint
> into an "only" constraint. Because that breaks the semantics for "only"
> constraints. If this sounds ok, I can whip up a patch for the same.
>
>
PFA, patch which does just this.

postgres=# alter table a add constraint chk check (ff1 > 0);
ERROR: constraint "chk" for relation "b" is an ONLY constraint. Cannot
merge

Regards,
Nikhils