Calling a function in a before delete trigger - oracle

Question

id like to call this function:
CREATE OR REPLACE PACKAGE orders_salary_manage2 AS
FUNCTION total_calc(p_order in NUMBER)
RETURN NUMBER;
END;
CREATE OR REPLACE PACKAGE BODY orders_salary_manage2 AS
tot_orders NUMBER;
FUNCTION total_calc(p_order in NUMBER)
RETURN NUMBER
IS
c_price product.unit_price%type;
c_prod_desc product.product_desc%type;
v_total_cost NUMBER := 0;
CURSOR c1 IS
SELECT product_desc, unit_price
FROM product
WHERE product_id IN (SELECT fk2_product_id
FROM order_line
WHERE fk1_order_id = p_order);
BEGIN
OPEN c1;
LOOP
FETCH c1 into c_prod_desc, c_price;
v_total_cost := v_total_cost + c_price;
EXIT WHEN c1%notfound;
END LOOP;
CLOSE c1;
return v_total_cost;
END;
from this trigger:
CREATE OR REPLACE TRIGGER trg_order_total
BEFORE DELETE ON placed_order
FOR EACH ROW
DECLARE
v_old_order NUMBER := :old.order_id;
BEGIN
total_calc(v_old_order);
END;
but i keep getting this error, note there is no error number just this:
Error at line 4: PL/SQL: Statement ignored
BEFORE DELETE ON placed_order
FOR EACH ROW
DECLARE
v_old_order NUMBER := :old.order_id;
BEGIN
im new to pl/sql and just not sure what is causing the problem. When a user deletes an order from the orders table the trigger should call the function to add up all the products on the order.
Thank you

Answer 1

(Considering your Package compiled with no errors) Use-
ret_val:= orders_salary_manage2.total_calc(v_old_order);
The ret_val must be a NUMBER since the package function total_calc returns a NUMBER. A function MUST always return its outcoume to a variable (like ret_val) depending on the type of the return value the data type of the variable must be declared.
The syntax to call Pacakaged Procedures and functions is -
<RETURN_VARIABLE> := PACKAGE_NAME.<FUNCTION_NAME>();
PACKAGE_NAME.<PROCEDURE_NAME>(); --Since Procedure never returns
Also note that if your package is in a different SCHEMA and has no PUBLIC SYNONYM then you will have to prefix the schema name like <SCHEMA>.PACKAGE_NAME.<FUNCTION_NAME>() (considering the calling schema has execute permissions on the package).
So,
CREATE OR REPLACE TRIGGER trg_order_total
BEFORE DELETE ON placed_order
FOR EACH ROW
DECLARE
v_old_order NUMBER := :old.order_id;
v_ret_val NUMBER := 0;
BEGIN
v_ret_val := orders_salary_manage2.total_calc(v_old_order);
--...Do stuff with v_ret_val
END;