Re: Inherit a primary key?

On Thu, 26 Jul 2001 08:04:58 +1000, Paul Gear <paulgear@bigfoot.com> wrote:
> Hi All,
>
> Can anyone tell me whether i am doing something wrong or if this is
> simply not supported at the moment?
>
> What i would like to do is have a generic object as the root of my
> table inheritance hierarchy, thus:
>
>     create table object (
>         id                  serial primary key,
>         label               text not null,
>         notes               text
>     );
>
> And then inherit my actual entities from object, like this:
>
>     create table bar (
>         name                text,
>         version             text
>     ) inherits ( object );
>
> Then i would like to refer to the inherited table, like this:
>
>     create table foo (
>         name    text,
>         barid    integer references bar,
>     );
>
> However, when i try to create foo, i get this:
>
>     NOTICE:  CREATE TABLE will create implicit trigger(s) for FOREIGN
> KEY check(s)
>     ERROR:  PRIMARY KEY for referenced table "bar" not found
>
> What seems to have happened is that all the fields of object were
> inherited by bar, but not the primary key.  So there is no primary key
> for foo to reference, and the references clause fails.
>
> What is the problem?  Is inheritance of primary keys not supported, or
> do i need to do something else?
>
> I'm using version 7.0.3 on Red Hat 7.1.
>


From the ToDo list:

Allow inherited tables to inerit index, UNIQUE contraint, and
primary key, foreign key.

There is also a page in ToDo detail about inheritance.

This one bit me before too. It seems like it would be a Good Thing.
Just waiting for someone to take on the challenge :)