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Re: "mirroring" a table - PostgreSQL 7.3.2

From: "C(dot) Bensend" <benny(at)bennyvision(dot)com>
To: pgsql-admin(at)postgresql(dot)org
Subject: Re: "mirroring" a table - PostgreSQL 7.3.2
Date: 2004-01-25 04:14:18
Message-ID: 53768.63.227.74.41.1075004080.squirrel@webmail.stinkweasel.net (view raw or flat)
Thread:
Lists: pgsql-admin
> when you drop a column). This is NOT "on the same level as a quick
> DROP/CREATE".

Hi Reece,

   My apologies to Tom - I certainly was not trying to disreguard or
"blow off" his advice.  I think my lack of understanding may have
manifested itself as dismissal.  I'm a systems/network guy, not a DBA
by any stretch of the word, and most of this is a real learning experience
for me.  :/

> Here's a proposal to get what you want: Create a super table bob_def and
> two sub tables bob and bob_test. Changes to the definition of bob_def
> (e.g., alter table add column...) will get immediately reflected in both
> children. You'll insert data into bob and bob_test; bob_def contains no
> rows. Selects on bob and bob_test are independent. In short, the
> definitions will always be consistent and the data will be completely
> independent. You could periodically truncate bob_test and insert ...
> select to mirror the data too.
>
> A lesser option is to have bob_test inherit from bob, then use rules to
> enforce the ONLY keyword for select/insert/update on bob. The
> implementation of this option is less clear to me and there are a few
> likely gotchas.

I am loath to ask for a hand-hold here, but could you explain a little
more about how to do such a thing?

>> CREATE TABLE test_bob AS ( SELECT * FROM bob WHERE '1' = '2' );
>
>
> I don't understand why this does what you want... it requires explicit
> intervention (meaning not "real time") to mirror the table definition.

This is just an example of what I need to do - just duplicate the table
structure exactly, and never mind the data.  I know it isn't the solution.
I just wanted folks to understand what I'd like to do.  :)

Thanks much for your help, Reece, it is greatly appreciated.  :)

Benny


-- 
"Have you ever tried simply turning off the TV, sitting down with your
children, and hitting them?"                   -- Bender, "Futurama"

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