FOR EACH STATEMENT triggers

I'd like to implement FOR EACH STATEMENT triggers. AFAICS it shouldn't
be too tricky -- so if there's some show-stopper that prevented it
from being done earlier, let me know now, please :-)

Some random notes on the implementation I'm thinking of:
       - in the function called by a per-statement trigger, no         references to the 'OLD' or 'NEW' rows will be
allowed
       - should we allow per-statement BEFORE triggers? DB2 doesn't,         but I'm not sure that's because they just
cutcorners, or if         there's some legitimate reason not to allow them. AFAICT SQL         200x doesn't specify
thatthey *aren't* allowed, so I'm         inclined to allow them...
 
       - if the statement effects zero rows, a per-statement trigger         is still executed
       - COPY executes per-statement INSERT triggers, to stay         consistent with the current behavior WRT per-row
INSERT        triggers
 
       - specifying 'FOR EACH xxx' in CREATE TRIGGER should now be         optional; if neither is specified, FOR EACH
STATEMENTis the         default. This is per SQL spec (SQL 200x, 11.39, 8)
 

Comments?

Cheers,

Neil       
-- 
Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC