Message-ID: <40D88CED.50903@archonet.com>
Date: Tue, 22 Jun 2004 20:47:57 +0100
From: Richard Huxton <dev@archonet.com>
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To: Bruno Wolff III <bruno@wolff.to>
Cc: Matthew Nuzum <matt@followers.net>, pgsql-sql@postgresql.org
Subject: Re: matching rows differing only by fkey,pkey
References: <20040622172704.GA19163@wolff.to>
	<200406221740.i5MHe6nb015623@ms-smtp-02.tampabay.rr.com>
	<20040622181649.GB20086@wolff.to>
In-Reply-To: <20040622181649.GB20086@wolff.to>
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Bruno Wolff III wrote:
> On Tue, Jun 22, 2004 at 13:40:03 -0400,
>   Matthew Nuzum <matt@followers.net> wrote:
> 
>>  The end result is to duplicate the data for a particular record in table
>>  "a" so that all of it's related data in tables "b" and "c" is duplicated.
>>Where "b" is the middle table in a many to many relationship.  For example,
>>
>>- a ----    - b ----    - c ----
>> aid  <--+   bid  <--+   cid
>> data1   +-->aid     +-->bid
>> data2       field1      info1
>> date3       field2      info2
>>
>>SELECT a.*,b.*,c.* from a,b,c where b.aid = a.aid and c.bid = b.bid;
>>
>>So, the goal is to duplicate an object that is made up of the data stored
>>across these three tables. 
[snip]
> Offhand I can't think of a way to avoid using a procedural language to walk
> through the b table so that you can easily keep track of which new bid
> corresponds to which old bid. However, writing a perl script or plsql
> function to do this for you shouldn't be difficult.

Screams out plpgsql to me - it's good at automating what is basically 
cut & paste of values.

-- 
   Richard Huxton
   Archonet Ltd