Currently this trigger on acs_objects is:
create function acs_objects_last_mod_update_tr () returns opaque as '
begin
new.last_modified := now();
return new;
end;' language 'plpgsql';
Which is annoying since if you want to change last_modified
you have to drop and recreate this trigger.
I would like to change it so that it reads
create function acs_objects_last_mod_update_tr () returns opaque as '
begin
if new.last_modified is null then
new.last_modified := old.last_modified;
else if new.last_modified = old.last_modified then
new.last_modified := now();
return new;
end;' language 'plpgsql';
what this would mean is that for changes which should preserve last_modified you could update and set last_modified = null to preserve the timestamp, the current behavior where updates don't touch last_modified would be the same, and for places where you are setting last_modified explicitly you could do so without dropping the trigger.
The only significant disadvantage is that if a script that did something like update last_modified to match an external timestamp (for a bulk load for example) got run twice you might end up with last_modified set to now for all updated rows (and you might also get the occasional update where the original and new ones just happen to match and the timestamp
is set to now anyway).
The motivation is that I want to be able to load mailing list archives into forums and set the creation and last modified dates to the right values. or have last_modified
in static pages reflect the timestamp on the file.
Anyone have any objection? Should this be a TIP?
