Am Sonntag, den 30.10.2005, 06:29 -0800 schrieb David Fetter:
> On Fri, Oct 28, 2005 at 09:57:03PM -0400, blackwater dev wrote:
> > In MySQL, I can use the replace statement which either updates the
> > data there or inserts it. Is there a comporable syntax to use in
> > postgreSQL?
>
> Not really, but here's an example which doesn't have the brokenness of
> MySQL's REPLACE INTO and doesn't have the race conditions that some
> others' proposals have.
>
> http://developer.postgresql.org/docs/postgres/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING
>
> Of course, it's not as nice and flexible as the SQL standard MERGE,
> but until that day comes, you can use that example.
In most cases, just DELETE and then INSERT should work perfectly.
(UPDATE and MERGE would cause dead tuples in the same way so in
the end they are only syntactical sugar)
Another way is a rule for insert which turns it into an update
in case the desired tuple is already existent.