Inherited tables and new fields

From: Jeff Boes <jboes(at)qtm(dot)net>
To: pgsql-sql(at)postgresql(dot)org
Subject: Inherited tables and new fields
Date: 2004-07-20 14:36:02
Message-ID: D5aLc.46510$5Y.46338@cyclops.nntpserver.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

This feels like a flaw in the way inherited tables work.

I have a "template" table used to create other tables (but not by
inheritance; instead the "daughter" tables are created via

create table draft_00123 as select * from draft_template where false;

This is done for somewhat historical reasons, because we weren't sure at
the time if we were going to stay with Pg and so we didn't use every
Pg-specific feature in the books.

Of course, we regret that ...

Now we have a function that spans all the daughter tables. That is, you
can do

select * from fn_all_drafts() ...

and get rows from each table.

Of course, had we used table inheritance, we'd do something like ...

select * from draft_template ...

but it wouldn't do exactly what we are doing now: that is,
fn_all_drafts() returns not only the contents of every row in the tables
draft_XXXXX, but also an extra column indicating which table that row
came from.

create table all_drafts (editor_id integer) inherits draft_template;

What frustrates me from time to time is that if "draft_template" is
altered to add a new column, then the function breaks because the new
column appears in "all_drafts" as *following* editor_id. The column
order messes up the code in the function, because it's expecting
all_drafts to look like draft_template, with editor_id added at the end.

Is this a mis-feature?

--
(Posted from an account used as a SPAM dump. If you really want to get
in touch with me, dump the 'jboes' and substitute 'mur'.)
________
Jeffery Boes <>< jboes(at)qtm(dot)net

Responses

Browse pgsql-sql by date

  From Date Subject
Next Message Caleb Simonyi-Gindele 2004-07-20 15:27:14 SELECT query/subquery problem
Previous Message Vic Ricker 2004-07-20 14:21:37 Re: How do I convice postgres to use an index?