Hi *,
suppose I have 2 tables
CREATE TABLE t1(
id uuid,
name text,
surname text,
...
PRIMARY KEY(id)
)
CREATE TABLE t2(
id uuid,
master_id uuid,
op_ts timestamp with time zone,
name text,
surname text,
...
PRIMARY KEY(id)
)
I need to write an AFTER TRIGGER on UPDATE so all columns of t1 go in the same columns in t2 (except for t1.id that goes in t2.master_id, and t2.op_ts gets now())
I cannot write an 1 to 1 column assignment (like NEW.name := OLD.name and so on) because the trigger has to be used on many tables, that has different (and evolving) schema and I don't want to write dozen of function that have to be frequently mantained.
I'm quite noob at pl-pgsql; at the moment I wrote this, but I can't "tell the function that fields are from OLD row" (the error is "missing FROM-clause entry for table 'old')
I tried also with field names alone (without OLD.), with no success.
Trigger is fired AFTER UPDATE in t1 (CREATE TRIGGER update_id AFTER UPDATE ON t1 FOR EACH ROW EXECUTE PROCEDURE update_op());
CREATE OR REPLACE FUNCTION update_op() RETURNS TRIGGER
AS $$
DECLARE
fieldlist text := (select string_agg(column_name, ', ')
from information_schema.columns c
where table_name = TG_TABLE_NAME and
(column_name <> 'id'));
oldfieldlist text := (select string_agg(column_name, ', OLD.')
from information_schema.columns c
where table_name = TG_TABLE_NAME and
(column_name <> 'id'));
BEGIN
EXECUTE 'INSERT INTO t2 (master_id, op_ts, '|| fieldlist ||') VALUES (OLD.id, now(), OLD.'||oldfieldlist||')' USING OLD;
RETURN NULL;
END;
$$
LANGUAGE 'plpgsql';
What am I missing?
Thanks,
Moreno