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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Plugge, Joe R. <JRPlugge@west.com>
Cc: Justin Graf <justin@magwerks.com>
Cc: pgsql-sql@postgresql.org <pgsql-sql@postgresql.org>
Subject: Re: Column Specific Update Trigger Routine
Date: Thu, 06 May 2010 17:13:40 -0400
Message-ID: <24219.1273180420@sss.pgh.pa.us> (raw)
In-Reply-To: <BD69807DAE0CE44CA00A8338D0FDD08302D2654164@oma00cexmbx03.corp.westworlds.com>
References: <4B54FDF3.4070601@gmx.net>
	<92869e661001190627i4d42e3?= =?utf-8?Q?68nbb0e96bf5c54ca76@mail.gmail.com>
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	<BD?= =?utf-8?Q?69807DAE0CE44CA00A8338D0FDD08302D2654129@oma00cexmbx03.corp.westwo?= =?utf-8?Q?rlds.com>
	<4BE32DA4.3040209@magwerks.com>
	<BD69807DAE0CE44CA00A8338D0FDD08302D2654164@oma00cexmbx03.corp.westworlds.com>

"Plugge, Joe R." <JRPlugge@west.com> writes:
> This is what I have and it seems to work:

>             IF OLD.password != NEW.password

It'd be better to write "IF OLD.password IS DISTINCT FROM NEW.password".
The way with != will not do what you want if one value is null and the
other isn't.  It's possible this doesn't matter in this particular case
(if password can't ever be null in this table), but being careful about
nulls is a good habit to cultivate.

			regards, tom lane



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