Condition: Always.
if startDate < enddate < now
past record, do not allow.
else if startdate < now < enddate
ensure start date was not changed.
allow update
update t_exhibition_locations
updating exhibition items trigger does the rest.
else if now < startdate < enddate
allow update.
update t_exhibition_locations
updating exhibition items trigger does the rest.
Condition: Always. if startDate < enddate < now past record, do not allow. else if startdate < now < enddate ensure start date was not changed. allow update update t_exhibition_locations updating exhibition items trigger does the rest. else if now < startdate < enddate allow update. update t_exhibition_locations updating exhibition items trigger does the rest.