Re: PRIMARY KEY and INHERITANCE

From: Horst Herb <hherb@malleenet.net.au>  Date: Mon, 1 Jan 2001 10:09:52 +1100

>> create table a (
>>        id serial primary key,
>>        something text
>> );
>>
>> create table b (
>>        morething text
>> ) inherits (a);
>>
>> create table c (
>>        trouble int references b;
>> );

>> NOTICE:  CREATE TABLE will create implicit trigger(s) for FOREIGN KEY
>> check(s) ERROR:  PRIMARY KEY for referenced table "b" not found
>
>
>> How is possible to resolve this bug?
>> How is possible to talk about a ORDBMS with this kind of error?

> It is not a bug, I would call it a missing feature. I had the same problem, 
> and somebody from this list helped me with a private email. I think this 
> should be included in the FAQ and general documentation.
> What happens is that the attribute "id" is inherited, but the index on "id" 
> is not. The workaround is:

> create unique index table_b_id on b(id);

> Then the index exists, and the foreign key can be referenced.

Thank you Horst,

I was very happy for this workaround: it could make me able to use classes
during the design and it could give me a power approach, but now:

\di            List of relations          Name            | Type  | Owner 
---------------------------+-------+-------a_pkey                    | index | fertable_b_id                | index |
fer

# create table c (test int references b);
NOTICE:  CREATE TABLE will create implicit trigger(s) for FOREIGN KEY check(s)
ERROR:  PRIMARY KEY for referenced table "b" not found

I've also tried to build b_pkey unique index:b_pkey                    | index | fer

The trouble still persists.


May someone give me another workaround for PostgreSQL 7.0.3?


Thank you in advance,               \fer