PostgreSQL: the good, the bad, and the ugly

"[...]that leads to the need for program logic to check for the existence of the row in question before choosing the correct command to make the change."

And we have a race condition here, if someone else inserts a new (and conflicting) row between the check and the change! Just kidding and nitpicking on a very good article, as usual around here; but I have seen that mistake made into code so many times, I just had to say it.