Re: UPSERT

Ühel kenal päeval, R, 2007-03-02 kell 10:13, kirjutas Tom Lane:
> Andrew Dunstan <andrew@dunslane.net> writes:
> > My instinct would be to follow your first strategy, i.e. detect which 
> > path is needed rather than try one and then if it fails do the other.
> 
> The very first thing you need to think about is how to solve the race
> condition problem, ie, two backends concurrently trying to insert
> identical data.  

Then one of them will update the data inserted by whoeved got the insert
first.

> Until you have a plausible mechanism for that, the
> whole thing is pie-in-the-sky.

Is'nt the standard way of doing it thus:

UPDATE
IF NOT FOUND THEN 
  INSERT
  IF DUPLICATE KEY THEN
    UPDATE
  END IF
END IF

At least this is how UPSERT is usually done in plpgsql


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