I'm planning on trying out a version
of the check done for foreign keys that does
a query on the fktable with a NOT EXISTS
subselect rather than the current run the
trigger for each row (thus doing one query
per row of the table). I want to see if this
tends to be faster than what we're doing now
and want to make sure noone has any general
objections to doing it this way (before
bothering to do it and timings).