how to fix the end of procedure trigger error - database

Question

is there a way to fix this error or there is something i am missing in my code,im learning postgresql and i have been working on table inheritance and triggers i have two tables the temporary_object table and the persons table the persons table inherits all the properties the the temporary object has,then i have created a trigger function on the persons table which checks the records with the same id before updating the tables my problem comes when i try to run the insert query,im getting these errors
ERROR: end of trigger procedure achieved without RETURN
CONTEXT: function PL / pgSQL muli_function ()
ERROR: end of trigger procedure achieved without RETURN
SQL-state: 2F005
Context: The PL / pgSQL muli_function ()
this is by insert query
INSERT INTO persons (id, time_create, time_dead, First_name, Last_name) values (1, '2011-10-07 15:25:00 EDT', '2011-10-07 3:25 PM EDT', 'sathiya', 'james');
and this my trigger function and trigger itself
CREATE FUNCTION muli_function() RETURNS trigger AS '
BEGIN
IF tg_op = ''UPDATE'' THEN
UPDATE persons
SET time_dead = NEW.time_create
Where
id = NEW.id
AND time_dead IS NULL
;
RETURN new;
END IF;
END
' LANGUAGE plpgsql;
CREATE TRIGGER sofgr BEFORE INSERT OR DELETE OR UPDATE
ON persons FOR each ROW
EXECUTE PROCEDURE muli_function();
and these are my two tables query
CREATE TABLE temporary_object
(
id integer NOT NULL,
time_create timestamp without time zone NOT NULL,
time_dead timestamp without time zone,
PRIMARY KEY (id, time_create)
);
CREATE TABLE persons
(
First_Name text,
Last_Name text
)
INHERITS (temporary_object);

Answer 1

Try this:
CREATE FUNCTION muli_function() RETURNS trigger AS '
BEGIN
IF tg_op = ''UPDATE'' THEN
UPDATE persons
SET time_dead = NEW.time_create
Where
id = NEW.id
AND time_dead IS NULL
;
END IF;
RETURN new;
END
' LANGUAGE plpgsql;
UPD Better something like this:
CREATE FUNCTION muli_function() RETURNS trigger AS '
BEGIN
IF tg_op = ''UPDATE'' THEN
IF NEW.time_dead IS NULL THEN
NEW.time_dead = NEW.time_create
END IF;
END IF;
RETURN new;
END
' LANGUAGE plpgsql;

Answer 2

You define the trigger procedure for an INSERT OR UPDATE trigger, but don't provide a case for the INSERT (just as mu is too short is commented), only the UPDATE. So the trigger executes the procedure for an INSERT, then it does not find anything to execute and exits without a RETURN, which is obviously an error.