Calculate the total value of payments with the procedures and triggers?

Question

Hello!
I work for a college project and I have a big problem because professor requires to do it by the examples he gives during the lecture. Here's an example that should be applied to its base, so please help!
I have three table with that should work:
Invoice (#number_of_invoices, date, comm, total_payment, number_of_customer, number_of_dispatch)
where:
number_of_invoices primary key (number),
date (date),
comm (var2),
total_payment is UDT (din - currency in my country) - in this field should be entered value is calculated
number_of_customer and number_of_dispatch (number) are foreign keys and they are not relevant for this example
Invoice_items (#serial_number, #number_of_invoices, quantity, pin)
serial_number primary key (number),
number_of_invoices primary key (number),
quantity (number),
pin foreign keys (number)
Item (#pin, name, price, tax, price_plus_tax)
pin primary key (number),
name (var2),
price, tax, UDT (din) not relevant for this example
price_plus_tax UDT (din)
These are the triggers and procedures with my calculation should be done:
trigger1:
CREATE OR REPLACE TRIGGER  "trg1"
BEFORE INSERT OR UPDATE OR DELETE ON Invoice_items
FOR EACH ROW
BEGIN  
     IF (INSERTING OR UPDATING)
     THEN     
          BEGIN Invoice_items.number_of_invoices := :NEW.number_of_invoices; END;
     ELSE
          BEGIN Invoice_items.number_of_invoices :=: OLD.number_of_invoices; END;  
     END IF;
END;trigger2:
CREATE OR REPLACE TRIGGER  "trg2"
AFTER INSERT OR UPDATE OR DELETE ON Invoice_items
DECLARE
doc NUMBER := Invoice_items.number_of_invoices;
BEGIN  
     entire_payment (doc);
END;procedure
CREATE OR REPLACE PROCEDURE  "entire_payment" (code_of_doc IN NUMBER) AS 
entire NUMBER := 0;
BEGIN 
     SELECT SUM (a.price_plus_tax * i.quantity) INTO entire
     FROM Item a join Invoice_items i on (a.pin = i.pin) 
     WHERE number_of_invoices = code_of_doc;
     UPDATE Invoice
     SET total_payment = entire
     WHERE number_of_invoices = code_of_doc;
END;As you can see the procedure is called from the triggers, I have a problem at the first trigger, and I think it will be even higher in procedure because UDT, field "total_payment".

Answer 1

I was not here a few days because I was trying to get additional information related to this problem. Professor gave me the information that I need to introduce a package and variable to get this thing work. But including that I still have problem. I hope that this time is less of a problem and that someone will be able to help me.
I also noticed that it was not a smart idea to try to translate the names of tables and attributes. That make trouble for me, especially you who are trying to understand and to help me, and absolutely nothing that will change the attribute and the table name will be. So this time I will set out the problem with the original name again to avoid confusion.
So, I try to base Implement optimization technique called: Repeating Single Detail with Master (so writes the slides that I received from professor, I hope that will mean something to you)
These are the lines of code that we get on the slides and should implement in the base, again I remind you that at this time in its original form, without translation.
- First create the package variable:
create or replace
package paket
AS
sifra number(10):=0;
end;This part is ok and it works.
- Secondly, it is necessary to create the first trigger:
create or replace
TRIGGER aktuelna_cena1
BEFORE INSERT OR UPDATE OR DELETE ON cena_artikla
FOR EACH ROW
BEGIN
     IF (INSERTING OR UPDATING)
     THEN      
          BEGIN paket.sifra := :NEW.sifra_artikla; END;
     ELSE
          BEGIN paket.sifra := :OLD.sifra_artikla; END;
    END IF;
END;This part is ok and working.
Now the problems begin.
- It is necessary to create another trigger that will call the procedure:
create or replace
TRIGGER aktuelna_cena2
AFTER INSERT OR UPDATE OR DELETE ON cena_artikla
DECLARE  
     s NUMBER := paket.sifra;
BEGIN  
     aktuelnacena (s);
END;I suppose the trigger have problem because procedure is not ok.
I will copy error that I get from the compiler:
Error(7,2): PL/SQL: Statement ignored
Error(7,2): PLS-00905: object NUMBER6.AKTUELNACENA is invalid
And finally, it is necessary to create the procedure:
create or replace
PROCEDURE  aktuelnacena (SifraPro IN NUMBER) AS 
aktCena artikal.aktuelna_cena%type;
BEGIN aktCena:=0;
                SELECT cena INTO aktCena
                FROM cena_artikla 
                WHERE sifra_artikla=SifraPro and datum_od=
                                (select max(datum_od)
                                from cena_artikla
                                where sifra_artikla = SifraPro and datum_od<=sysdate); 
                UPDATE artikal
                SET aktuelna_cena = aktCena
                WHERE sifra_artikla = SifraPro;
END;I will copy error that I get from the compiler:
Error(10,57): PLS-00103: Encountered the symbol " " when expecting one of the following: ( begin case declare end exception exit for goto if loop mod null pragma raise return select update while with << continue close current delete fetch lock insert open rollback savepoint set sql execute commit forall merge pipe purge The symbol " " was ignored.
Tables I work with are:
Artikal (sifra_artikla, naziv, aktuelna_cena),
Cena_artikla (sifra_artikla, datum_od, cena)
You will notice that this differs from the first problem, but my task is to implement the two optimization techniques and my base. Both techniques are quite similar and I hope that I now have enough information to help me. I suppose that when this problem is solved the othet one will too!
Thank in advance!