--On 13. September 2013 20:17:19 -0400 Robert Haas <robertmhaas@gmail.com>
wrote:
> You're missing the point. Peter wasn't worried that your patch throws
> an error; he's concerned about the fact that it doesn't.
>
> In PostgreSQL, you can only create the following view because test1
> has a primary key over column a:
>
> => create table test1 (a int constraint pk primary key, b text);
> => create view test2 as select a, b from test1 group by a;
> => alter table test1 drop constraint pk;
>
> The reason that, if the primary key weren't there, it would be
> ambiguous which row should be returned as among multiple values where
> a is equal and b is not. If you can disable the constraint, then you
> can create precisely that problem.
Hmm not sure i understand this argument either: this patch doesn't allow
disabling a primary key. It only supports FKs and CHECK constraints
explicitly.
--
Thanks
Bernd