a stored function for a trigger

audit_trigger.sql

CREATE FUNCTION account_audit_func()
RETURNS TRIGGER
AS $$
BEGIN
IF TG_OP = 'INSERT' THEN
  INSERT INTO account_audit (operation, account_id, account_name, debt, balance) VALUES
       (TG_OP, NEW.*);
  RETURN NEW;
ELSIF TG_OP = 'UPDATE' THEN
   INSERT INTO account_audit (operation, account_id, account_name, debt, balance) VALUES
        (TG_OP, NEW.*);
   RETURN NEW;
ELSIF TG_OP = 'DELETE' THEN
   INSERT INTO account_audit (operation, account_id, account_name, debt, balance) VALUES
        (TG_OP, OLD.*);
   RETURN OLD;
END IF;
END;
$$
LANGUAGE plpgsql;