Rules problem

Hello I’m Paola and I have an urgent problem. First I did a trigger to delete on cascade but didn’t work, then I did a rule for delete on cascade but they sometimes delete and sometimes don’t.

This is the trigger:

ELSIF TG_OP = ''DELETE'' THEN
old.action := ''DELETE'';
-- first, deletes on items table
-- DELETE FROM items WHERE item_id = old.item_id;

-- second, insert on log table
SELECT INTO version_val version FROM customers_log WHERE customer_id=old.customer_id AND item_id=old.item_id ORDER BY version DESC LIMIT 1;
IF FOUND THEN
version_val := version_val + 1;
INSERT INTO customers_log(item_id, customer_id, customer, action, action_date, author, version) VALUES (old.item_id, old.customer_id, old.customer, old.action, old.action_date, old.author, version_val);
RETURN old;
ELSE
-- RAISE EXCEPTION ''the value cannot have only an DELETE value. Security error (first: INSERT, after: UPDATE OR DELETE) ON customers DELETE TRIGGER'';
RETURN old;
END IF;
END IF;


This is the whole function:

CREATE FUNCTION customers_check_trg() RETURNS OPAQUE AS '
DECLARE
version_val integer :=0;
BEGIN
IF TG_OP = ''INSERT'' THEN
new.action := ''INSERT'';
SELECT INTO version_val version FROM customers_log WHERE customer_id=new.customer_id AND item_id=new.item_id ORDER BY version DESC LIMIT 1;
IF FOUND THEN
version_val := version_val + 1;
INSERT INTO customers_log(item_id, customer_id, customer, action, action_date, author, version) VALUES (new.item_id, new.customer_id, new.customer, new.action, new.action_date, new.author, version_val);
new.version := version_val;
RETURN new;
ELSE
INSERT INTO customers_log(item_id, customer_id, customer, action, action_date, author, version) VALUES (new.item_id, new.customer_id, new.customer, new.action, new.action_date, new.author, 1);
new.version := 1;
RETURN new;
END IF;
ELSIF TG_OP = ''UPDATE'' THEN
new.action := ''UPDATE'';
SELECT INTO version_val version FROM customers_log WHERE customer_id=new.customer_id AND item_id=new.item_id ORDER BY version DESC LIMIT 1;
IF FOUND THEN
version_val := version_val + 1;
INSERT INTO customers_log(item_id, customer_id, customer, action, action_date, author, version) VALUES (new.item_id, new.customer_id, new.customer, new.action, new.action_date, new.author, version_val);
new.version := version_val;
RETURN new;
ELSE
-- RAISE EXCEPTION ''the value cannot have only an UPDATE value. Security error (first: INSERT, after: UPDATE OR DELETE)ON customers UPDATE TRIGGER'';
RETURN new;
END IF;
ELSIF TG_OP = ''DELETE'' THEN
old.action := ''DELETE'';
-- first, deletes on items table
-- DELETE FROM items WHERE item_id = old.item_id;

-- second, insert on log table
SELECT INTO version_val version FROM customers_log WHERE customer_id=old.customer_id AND item_id=old.item_id ORDER BY version DESC LIMIT 1;
IF FOUND THEN
version_val := version_val + 1;
INSERT INTO customers_log(item_id, customer_id, customer, action, action_date, author, version) VALUES (old.item_id, old.customer_id, old.customer, old.action, old.action_date, old.author, version_val);
RETURN old;
ELSE
-- RAISE EXCEPTION ''the value cannot have only an DELETE value. Security error (first: INSERT, after: UPDATE OR DELETE) ON customers DELETE TRIGGER'';
RETURN old;
END IF;
END IF;
END;
' LANGUAGE 'plpgsql';

CREATE TRIGGER customers_trg BEFORE INSERT OR UPDATE OR DELETE ON customers
FOR EACH ROW EXECUTE PROCEDURE customers_check_trg();

This is the rule:

CREATE RULE customers_rule AS
ON DELETE TO customers DO DELETE FROM items WHERE item_id = old.item_id;

and sometimes appears this error:

ERROR: record "old" has no field named "item_id"

The create table statements are:

CREATE SEQUENCE customers_customer_id_seq
START 1
INCREMENT 1
MAXVALUE 9223372036854775807
MINVALUE 1
CACHE 1;

CREATE TABLE customers (
item_id integer NOT NULL,
customer_id bigint DEFAULT nextval('"customers_customer_id_seq"'::text) NOT NULL,
customer character varying(255) NOT NULL,
"action" character varying(50) NOT NULL,
action_date timestamp with time zone DEFAULT now(),
author character varying(24) NOT NULL,
"version" integer NOT NULL
);

CREATE SEQUENCE customers_log_id_seq
START 1
INCREMENT 1
MAXVALUE 9223372036854775807
MINVALUE 1
CACHE 1;


CREATE TABLE customers_log (
id integer DEFAULT nextval('"customers_log_id_seq"'::text) NOT NULL,
item_id integer NOT NULL,
customer_id bigint NOT NULL,
customer character varying(255) NOT NULL,
"action" character varying(50) NOT NULL,
action_date timestamp with time zone DEFAULT now(),
author character varying(24) NOT NULL,
"version" integer NOT NULL
);

I use the log table to record every change in every record.

What can I do?