PL/SQL table level trigger running after second update - sql

Question

I have this problem whith this trigger which is calling a procedure updating a table after updating a row in other table.The problem is that you have to update table STAVKARACUNA two times to table RACUN update but it uses old values. Here is a code of both:
Here is a code of aa procedure:
create or replace PROCEDURE ukupnaCenaRacun (SIF IN VARCHAR2) AS
SUMA float := 0;
suma2 float := 0;
Mesec NUMBER;
popust float :=0.1;
BEGIN
SELECT SUM(iznos) INTO SUMA
FROM STAVKARACUNA
WHERE SIF = SIFRARAC;
SELECT SUM(vredrobe*pdv) INTO SUMA2
FROM STAVKARACUNA
WHERE SIF = SIFRARAC;
SELECT EXTRACT (MONTH FROM DATUM) INTO Mesec FROM RACUN WHERE SIF=SIFRARAC;
IF(Mesec = 1) THEN
UPDATE RACUN
SET PDVIZNOS = SUMA2, ukupnozanaplatu = suma*(1-popust)
WHERE SIFRARAC=SIF;
END IF;
IF (MESEC != 1) THEN
UPDATE RACUN
SET PDVIZNOS = SUMA2, ukupnozanaplatu = suma
WHERE SIFRARAC=SIF;
END IF;
END;
Here is a trigger:
create or replace TRIGGER "UKUPNACENA_RACUN_UKUPNO"
AFTER INSERT OR UPDATE OR DELETE OF CENA,KOL,PDV ON STAVKARACUNA
DECLARE
SIF VARCHAR2(20) := PACKAGE_STAVKARACUNA.SIFRARAC;
BEGIN
PACKAGE_STAVKARACUNA.ISKLJUCI_TRIGER('FORBID_UPDATING');
ukupnaCenaRacun(SIF);
PACKAGE_STAVKARACUNA.UKLJUCI_TRIGER('FORBID_UPDATING');
END;
The problem is when a table STAVKARACUNA is updated, nothing happens with table RACUN, but next time table STAVKARACUNA is updated the data in table RACUN is updated but with old values.
Thank you very much.

Answer 1

Are you aware that a trigger for an event on a table should not directly access that table? The code is inside a DML event. The table is right in the middle of being altered in some say. So any query back to the same table could well attempt to read data that is in the process of being changed. It could try to read data that does not quite exist before a commit is performed or is one value now but will be a different value once a commit is performed. The table is mutating.
This goes for any code outside the trigger that the triggers calls. So the ukupnaCenaRacun procedure is executed in the context of the trigger. Yet it goes out and queries table STAVKARACUNA in two places (which can be placed in a single query but that is neither here nor there).
Since you're not getting a mutating table error, I can only assume that the update is not taking place until after the triggering event is committed but then you won't see the results until after that is committed sometime later -- like when the second update is committed.
That explanation actually sounds hollow to me as I have always thought that all activity performed by a trigger is committed or rolled back as part of one transaction. But that is the action you are describing.
It appears that SIF is a package variable defined in the package spec. Since everything in the procedure keys off that value and the trigger doesn't change the value, can't SUMA and SUMA2 also be defined as variables, values to be updated whenever SIF changes?