Message-ID: <3F84CADA.6050905@Yahoo.com>
Date: Wed, 08 Oct 2003 22:41:30 -0400
From: Jan Wieck <JanWieck@Yahoo.com>
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To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Christopher Kings-Lynne <chriskl@familyhealth.com.au>,
	Stephan Szabo <sszabo@megazone.bigpanda.com>, Tom Lane <tgl@sss.pgh.pa.us>,
	Peter Childs <Blue.Dragon@blueyonder.co.uk>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: ADD FOREIGN KEY (was Re: [GENERAL] 7.4Beta)
References: <200310090210.h992A7X27225@candle.pha.pa.us>
In-Reply-To: <200310090210.h992A7X27225@candle.pha.pa.us>
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Bruce Momjian wrote:

> Christopher Kings-Lynne wrote:
>> 
>> >>Well, with the CREATE CONSTRAINT TRIGGER you _can_, but we already have 
>> >>a consensus that we don't _want_ that. Probably we should declare it 
>> >>deprecated and remove it in 7.5. And the option currently under 
>> >>discussion is exactly what will cause ALTER TABLE to let you, but IMHO 
>> >>that _should_ be restricted.
>> 
>> How can we ever remove it - what about people upgrading from 7.0, 7.1, 
>> 7.2?  Also, people upgrading from 7.3 who've never heard of adddepend...
> 
> Not sure.  We can remove documentation about it, at least.
> 

If the idea is to support any 7.n -> 7.m (where n < m) upgrade directly, 
then it's IMHO time for 8.0 and clearly stating that 7.x -> 8.y only is 
supported as 7.x -> 7.3 -> 8.0 -> 8.y and "you're on your own with any 
other attempt".

Don't get this wrong, I am a big friend of easy upgrades. But I am not a 
big friend of making improvements impossible by "backward compatibility 
forever". It was the "backward compatibility" to CP/M-80 (v2.2) that 
caused MS-DOS 7.0 to have a maximum commandline length of 127 characters 
... that was taking compatibility too far. Well, M$ took it too far the 
other way from there and is compatible to nothing any more, not even to 
themself ... but at least they learned from that mistake.


Jan

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