Message-ID: <20040104185444.78502.qmail@web13808.mail.yahoo.com>
Date: Sun, 4 Jan 2004 10:54:44 -0800 (PST)
From: Chris Gamache <cgg007@yahoo.com>
Reply-To: cgg007@yahoo.com
Subject: Historic Query using a view/function ?
To: pgsql-sql@postgresql.org
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

...Postgresql 7.2...

I'm building the history of a table using rules. I've been trying to figure out
a way to select on a table as it would have appeared at a point-in-time. I
can't seem to wrap my brain around the problem, tho.

Given some tables

CREATE TABLE list (
  num int4 NOT NULL, 
  name varchar(50), 
  type varchar(50), 
  modified timestamptz DEFAULT ('now'::text)::timestamp(6) with time zone, 
  CONSTRAINT list_pkey PRIMARY KEY (num)
) WITH OIDS;

CREATE TABLE list_log (
  num int4 NOT NULL, 
  name varchar(50), 
  type varchar(50), 
  modified timestamptz DEFAULT ('now'::text)::timestamp(6) with time zone, 
  mod_type varchar(3), 
  log_date timestamptz DEFAULT ('now'::text)::timestamp(6) with time zone
) WITH OIDS;

And some rules...

CREATE RULE list_del AS ON DELETE TO list DO INSERT INTO list_log (num, name,
type, modified, mod_type) VALUES (old.num, old.name, old.type, old.modified,
'D'::"varchar");

CREATE RULE list_upd AS ON UPDATE TO list WHERE ((old.name <> new.name) OR
(old.type <> new.type)) DO INSERT INTO list_log (num, name, type, modified,
mod_type) VALUES (old.num, old.name, old.type, old.modified, 'U'::"varchar");

It'd be great to be able to do something like...

SELECT * FROM hist_list('10/10/2003'::date) WHERE name like '%Jones';

... I don't think Functions can return tables in 7.2 ... Can anyone think of a
way around this?

CG


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