On Fri, 2002-08-02 at 22:39, cbbrowne@cbbrowne.com wrote:
> On 29 Jul 2002 18:27:40 MDT, the world broke into rejoicing as
> Stephen Deasey <stephen@bollocks.net> said:
> > Curt Sampson wrote:
> >> I'm still waiting to find out just what advantage table inheritance
> >> offers. I've asked a couple of times here, and nobody has even
> >> started to come up with anything.
>
> > Table inheritance offers data model extensibility. New (derived) tables
> > can be added to the system, and will work with existing code that
> > operates on the base tables, without having to hack up all the code.
>
> But it kind of begs the question of why you're creating the new table in
> the first place.
>
> The new table certainly _won't_ work with existing code, at least from
> the perspective that the existing code doesn't _refer_ to that table.
The beuty of OO is that it does not need to :
hannu=# create table animal (name text, legcount int);
CREATE
hannu=# insert into animal values('pig',4);
INSERT 34183 1
hannu=# select * from animal;name | legcount
------+----------pig | 4
(1 row)
hannu=# create table bird (wingcount int) inherits (animal);
CREATE
hannu=# insert into bird values('hen',2,2);
INSERT 34189 1
hannu=# select * from animal;name | legcount
------+----------pig | 4hen | 2
(2 rows)
------------------
Hannu
