Subject: Re: [HACKERS] What can we learn from MySQL?
From: Jeff Davis <jdavis-pgsql@empires.org>
To: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
Cc: PostgreSQL advocacy <pgsql-advocacy@postgresql.org>
In-Reply-To: <4088B944.1050007@familyhealth.com.au>
References: <200404230409.i3N49jC02890@candle.pha.pa.us>
	<4088B944.1050007@familyhealth.com.au>
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Message-Id: <1082708197.32307.1136.camel@jeff>
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Date: Fri, 23 Apr 2004 01:16:38 -0700
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> I have already told Bruce at length about the single most common 
> complaint in the phpPgAdmin lists and in the IRC channel: the inability 
> to change column types.  I think we should listen to the punters on that 
> one.
> 

Maybe a simple and less dangerous option would be to add a column of the
new type, rename the old column and hide it, and select from the old
column and cast it to the new column? Is that a feasible implementation?
If I really need to change a column, that's what I'd do.

It's certainly less dangerous than MySQL. I remember a horror story
watching my column silently cast itself to a bunch of blank values in
MySQL. In postgres you'd just be able to undo it or fix the problem
since the data is still there. I also understand that MySQL has to copy
the entire table or something insane like that, so we could use the
opportunity to brag about how much more efficient we are for large
tables.

	Regards,
		Jeff Davis