Обсуждение: Inheritance and such

Hi everyone,

I ran into a brick wall when I realized that inheritance in postgres isnt
really there...

Here's a description of the relevant part of my schema.

CREATE TABLE base (
id serial not null primary key,
<some base columns>
);

CREATE TABLE specialized (
<some specialized columns>
) INHERITS base;

CREATE TABLE specialized2 (
<some specialized columns>
) INHERITS base;

CREATE TABLE events (
id serial not null primary key,
baseid int references base(id)
<some other columns>
);

This does not work if I load a bunch of records into specialized and then try
to refer to the id's through the event's table because Postgres doesn't do
N-table indexes where N is greater than 1 :-P

This whole part of my schema, if it worked, would be so incredibly useful, as
I would be able to add as many specialized tables as needed, and still use
the same sql to create events for them, and access their base table's data,
etc.

So I have 3 questions: Is any work being done currently to fix our
implementation of inheritance? How much work would it take to do this? and
lastly, how can I implement my schema to do something similar, emulated, or
otherwise that will work with postgres as it is now?

Thanks,

John Hughes
Wetleads.com

On Fri, Apr 01, 2005 at 09:51:25AM -0600,
 John Hughes <johnh@wetleads.com> wrote
 a message of 49 lines which said:

> I ran into a brick wall when I realized that inheritance in postgres
> isnt really there...

I have a problem which MAY be in the same category.

CREATE TABLE base (
 id serial not null primary key,
 <some base columns>
);

CREATE TABLE specialized (
<some specialized columns>
) INHERITS base;

Now, I try to set up a trigger AFTER UPDATE ON base but, when I update
"specialized", the trigger is not called. Same thing with CREATE or
DELETE. I have to define the trigger to be AFTER UPDATE ON
specialized. Is it normal?

PostgreSQL  7.4

Stephane Bortzmeyer schrieb:

>
>I have a problem which MAY be in the same category.
>
>CREATE TABLE base (
> id serial not null primary key,
> <some base columns>
>);
>
>CREATE TABLE specialized (
><some specialized columns>
>) INHERITS base;
>
>Now, I try to set up a trigger AFTER UPDATE ON base but, when I update
>"specialized", the trigger is not called. Same thing with CREATE or
>DELETE. I have to define the trigger to be AFTER UPDATE ON
>specialized. Is it normal?
>
>
>
Yes, thats known.

You have to define a trigger on each child table. You can point that
trigger on the same function.

Daniel.