Re: [GENERAL] Inherited constraints and search paths (was

Поиск
Список
Период
Сортировка
От Bruce Momjian
Тема Re: [GENERAL] Inherited constraints and search paths (was
Дата
Msg-id 200505302108.j4UL8Nv17903@candle.pha.pa.us
обсуждение исходный текст
Ответ на Re: [GENERAL] Inherited constraints and search paths (was Re:  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-hackers
Added to TODO:

    * Prevent child tables from altering constraints like CHECK that were
      inherited from the parent table


---------------------------------------------------------------------------

Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > Doing anything to restrict dropping of inherited constraints seems like
> > wasted effort and potentially annoying anyhow.
>
> Uh, why?  Arguably the constraints are as much part of the parent table
> definition as the columns themselves.  If you had "check (f1 > 0)" in
> the definition of a table, wouldn't you be pretty surprised to select
> from it and find rows with f1 < 0?
>
> regression=# create table parent(f1 int check (f1 > 0));
> CREATE TABLE
> regression=# create table child() inherits(parent);
> CREATE TABLE
> regression=# alter table child drop constraint parent_f1_check;
> ALTER TABLE
> regression=# insert into child values(-1);
> INSERT 0 1
> regression=# select * from parent;
>  f1
> ----
>  -1
> (1 row)
>
> I think a good argument can be made that the above behavior is a bug,
> and that the ALTER command should have been rejected.  We've gone to
> great lengths to make sure you can't ALTER a child table to make it
> incompatible with the parent in terms of the column names and types;
> shouldn't this be true of check constraints as well?
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
>       subscribe-nomail command to majordomo@postgresql.org so that your
>       message can get through to the mailing list cleanly
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

В списке pgsql-hackers по дате отправления:

Предыдущее
От: Bruce Momjian
Дата:
Сообщение: Re: [PATCHES] Adding \x escape processing to COPY, psql, backend
Следующее
От: Mark Kirkwood
Дата:
Сообщение: Re: pg_buffercache causes assertion failure