Message-ID: <20050404100102.z7ohducpsei8s0c8@www.presserv.org>
Date: Mon,  4 Apr 2005 10:01:02 -0300
From: lucas@presserv.org
To: pgsql-sql@postgresql.org
Subject: Chield Serial
MIME-Version: 1.0
Content-Type: text/plain;
	charset=ISO-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 7bit
User-Agent: Internet Messaging Program (IMP) H3 (4.0)

Hi.
Is there a way to make a serial columm that works with father table???
I.e:
 I have created a table called "vending" and its chield table called "items".
 The items table have a serial columm, but I need the serial colum starts with 0
for each vending.

 create table vending (
  id serial primary key,  --Ok, this serial: 0 - 9999xxx
  date_ date
 );
 create table items (
  vending_id references vending,
  items_id   serial,  -- THIS SERIAL NEED to start 0 for each vending_id
  primary key (vending_id,items_id)
 );
 insert into vending values (1,now());
 insert into vending values (2,now());
 insert into items values (1);
 insert into items values (1);
 insert into items values (2);
 insert into items values (2);
 select * from items;

 vending_id  |  items_id
          1  |         1
          1  |         2
          2  |         3    <<=== Here! The items_id need to be 1 (start again
for each vending_id)
          2  |         4    <<==
Thanks all.