Message-ID: <3E6EB296.4020800@oasis.net.au>
Date: Wed, 12 Mar 2003 14:07:50 +1000
From: Rudi Starcevic <rudi@oasis.net.au>
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To: pgsql-sql@postgresql.org
Subject: Re: Table Updates ..
References: <3E6EAE99.8030005@oasis.net.au>
	<200303111957.23061.josh@agliodbs.com>
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Josh,

Thanks for that.
You're suggestion is how I currently have it.
However some other's had doubted my method and suggested the logging 
table(s).
Keeping is simple is much better.

Thanks again.
Regards
Rudi.


Josh Berkus wrote:

>Rudi,
>
>  
>
>>If I have 3 tables :
>>
>>orders,
>>products,
>>orders_products ( join table for orders and products )
>>
>>If I insert an order with two products I have:
>>
>>2 rows in the products table, ( the two products )
>>1 row in the orders table and ( one order )
>>2 rows in the orders_products table. ( two products for this order )
>>
>>So far so good. All that works well.
>>But what if next week one the the products in the products table is 
>>updated and changed ?
>>Then my order from last week is now different -- corrupted. It links to 
>>the same product_id but the product is changed.
>>    
>>
>
>If you're concerned with "freezing" the product characteristics at the time of 
>the order, the answer is to add all or most of the columns in the products 
>table to orders_products.   Then, at the time of order finalization 
>(shipping? not sure) you copy those columns from products to order_products.
>
>If you're into ORDMBS, you could even create orders_products as inheriting 
>products.  But this isnt' required.
>
>This will work better than a monthly log.
>
>  
>