On May 7, 2005, at 1:10, Tom Lane wrote:
Michael Glaesemann <grzm@xxxxxxxxxxxxx> writes:I thought that the unique key would be checked at the end of the update
statement:
No, it's never worked that way. Each row is checked as it is inserted.
With an example like this, you may or may not get a failure depending on
chance physical ordering of rows.
This is not per spec, and I believe we have a TODO to fix it, but a fix is far from trivial.
Thanks for clarifying this point. I've since made a simple workaround for my particular situation:
update a1 set a_id = (-1) * (a_id + 1); update a1 set a_id = (-1) * (a_id);
This relies on all a_id values to have the same sign (or at least satisfy unique(abs(a_id))), which is true in my case.
Thanks again!
Michael Glaesemann grzm myrealbox com
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