Vance Maverick wrote:
I have a bunch of tables that are similar in some ways, and I'm about to
put triggers on them. The triggers will all do essentially the same
thing -- the only wrinkle is that the name of the column they operate on
varies from table to table. I'd like to have just one trigger function,
written 'dynamically' so it can take the name of the column as a trigger
parameter (in TG_ARGV). For example, given tables
CREATE TABLE a (aa INT);
CREATE TABLE b (bb INT);
I'd like to be able to write a trigger function foo() such that with
trigger declarations
CREATE TRIGGER a_foo AFTER INSERT OR UPDATE OR DELETE ON a
FOR EACH ROW EXECUTE PROCEDURE foo('aa');
CREATE TRIGGER b_foo AFTER INSERT OR UPDATE OR DELETE ON b
FOR EACH ROW EXECUTE PROCEDURE foo('bb');
the logic in foo() reads columns a.aa or b.bb respectively.
I've tried composing a SQL string including the text 'NEW.aa' or
'NEW.bb' appropriately, and then passing this to EXECUTE. This fails:
ERROR: NEW used in query that is not in a rule
Any suggestions?
If you just need which table triggered the function then |TG_TABLE_NAME|
may be simpler than passing parameters.
Something like this will probably work for you (replace the raise notice
with whatever you have to do)
create or replace function atest() returns trigger as $$
declare
avalue int;
tblfld text;
begin
tblfld := tg_argv[0];
if tblfld = 'aa' then
avalue := new.aa;
else
if tblfld = 'bb' then
avalue := new.bb;
end if;
end if;
raise notice '%',avalue;
return new;
end;
$$ language plpgsql;
klint.
--
Klint Gore
Database Manager
Sheep CRC
A.G.B.U.
University of New England
Armidale NSW 2350
Ph: 02 6773 3789
Fax: 02 6773 3266
EMail: kgore4@xxxxxxxxxx
