Re: Why the ERROR: duplicate key violates uniqueconstraint "master_pkey" is raised? - Is this a Bug?

From: Reece Hart <reece(at)harts(dot)net>
To: Anoo Sivadasan Pillai <aspillai(at)in(dot)rm(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Why the ERROR: duplicate key violates uniqueconstraint "master_pkey" is raised? - Is this a Bug?
Date: 2007-09-25 05:02:45
Message-ID: 1190696565.20315.22.camel@snafu
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On Tue, 2007-09-25 at 10:06 +0530, Anoo Sivadasan Pillai wrote:

> But since you can’t control the order, it is likely that the operation
> will sometimes and will succeed sometimes, with the same data.. Weird
> I feel .

Not so weird (IMO). Many databases will return rows unordered unless you
specify otherwise. Once one understands that uniqueness constraints are
evaluated immediately and that rows are visited unordered, it's not so
weird.

> The work around given by you will work, Does it mean that whenever we
> are updating a unique key we have to take this precaution ?

Probably. I suspect that you're using unique or primary keys to imply
some meaning that would be better stored elsewhere, and definitely NOT
in a primary key. Perhaps you should consider refactoring your design.
You're doing something wrong if you find that you need to update primary
keys routinely.

-Reece

--
Reece Hart, http://harts.net/reece/, GPG:0x25EC91A0

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