Retraction of the previous (I realize SELECT FOR UPDATE can be useful
with Tom's method)
>Note: after thinking a little about it there's no need to use SELECT
>FOR UPDATE with Tom's method. A regular UPDATE will do (it does its
>own locking all by itself for only the time needed).
>
>(Therefore, if Tom's method would be the only recommendable one, the
>command SELECT FOR UPDATE would be without purpose. From this again
>I deduce that it originally must have been meant for use in long
>lasting transactions.)