Oracle Compound Trigger Mutation Table - oracle

Question

I'm trying to create a compound trigger to avoid the mutation problem.
I've a table and a python's procedure that perfoms a transaction insert. The table has n fields.
What I´m trying to do is when a value of one of those fields is negative, then do not perform the operation , and insert the value from the previous record of the field (prior to insert) of the table. Another concern is that one of the fields is and id, to distinguish between sites.
For no, this is the code I've, Considering only one field (KWHGEN):
CREATE OR REPLACE TRIGGER "CIRCU3".D_measures_TP_test
--FOR INSERT OR UPDATE ON T_MEASURES_TP_NEW
FOR INSERT ON T_MEASURES_TP_NEW
COMPOUND TRIGGER
VAL_KWHGEN NUMBER(21,2);
VAL_autoin NUMBER (19,0);
AFTER EACH ROW IS
BEGIN
SELECT autoin, KWHGEN INTO VAL_ID_MED, VAL_KWHGEN FROM
(SELECT *
FROM T_measures_TP_NEW WHERE ID_site = :NEW.ID_site
ORDER BY TIMESTAMP DESC)
WHERE ROWNUM = 1;
IF :NEW.KWHGEN <0
THEN UPDATE T_MEASURES_TP_NEW SET KWHGEN = VAL_KWHGEN WHERE autoin = VAL_autoin;
END IF;
END AFTER EACH ROW;
END D_MEASURES_TP_test;
But the mutation error is following me ;-)

Answer 1

You have created trigger on T_MEASURES_TP_NEW and then updating same table T_MEASURES_TP_NEW within trigger. This will again call your trigger.
If the first select in trigger again returns negative value in VAL_KWHGEN then mutating error will follow you.

Answer 2

You defined only an AFTER EACH block, nothing else. This is the same as creating a row-level trigger (i.e. using FOR EACH ROW)
It must be like this (not tested):
CREATE OR REPLACE TRIGGER "CIRCU3".D_measures_TP_test
FOR INSERT ON T_MEASURES_TP_NEW
COMPOUND TRIGGER
VAL_KWHGEN NUMBER(21,2);
VAL_autoin NUMBER (19,0);
TYPE RowIdTableType IS TABLE OF ROWID;
TYPE KWHGENTableType IS TABLE OF T_MEASURES_TP_NEW.KWHGEN%TYPE;
RowIdTable RowIdTableType;
KWHGENTable KWHGENTableType;
BEFORE STATEMENT IS
BEGIN
RowIdTable := RowIdTable();
KWHGENTable := KWHGENTableType();
END BEFORE STATEMENT;
BEFORE EACH ROW IS
BEGIN
RowIdTable.EXTEND;
RowIdTable(RowIdTable.LAST) := :NEW.ROWID;
KWHGENTable.EXTEND;
KWHGENTable(RowIdTable.LAST) := :NEW.KWHGEN;
END BEFORE EACH ROW;
AFTER STATEMENT IS
BEGIN
FOR i IN RowIdTable.FIRST..RowIdTable.LAST LOOP
SELECT
DISTINCT MIN(autoin) OVER (ORDER BY TIMESTAMP DESC),
DISTINCT MIN(KWHGEN) OVER (ORDER BY TIMESTAMP DESC)
INTO VAL_ID_MED, VAL_KWHGEN
FROM T_measures_TP_NEW
WHERE ROWID = RowIdTable(i);
IF KWHGENTable(i) < 0
THEN UPDATE T_MEASURES_TP_NEW
SET KWHGEN = VAL_KWHGEN
WHERE autoin = VAL_autoin;
END IF;
END LOOP;
END AFTER STATEMENT;
END;
/

Answer 3

OK, I do have a solution:
1.- Create a package where record the new insert data (BEFORE)
create or replace PACKAGE PCK_MEDIDAS_TP AS
TYPE DATOS_MEDIDAS_TP IS RECORD(
v_id_sede NUMBER (10,0),
v_id_med NUMBER (10,0),
v_kwhGEN NUMBER (21,2),
v_timestamp TIMESTAMP
);
type T_MEDTP is table of DATOS_MEDIDAS_TP index by binary_integer;
tabla_medidas_tp T_MEDTP;
END PCK_MEDIDAS_TP;
2.- Create a procedure each row (BEFORE) to read the new insert data and then record them into de package's table.
create or replace TRIGGER "CIRCU3".D_MEDIDAS_TP_test
BEFORE INSERT ON T_MEDIDAS_TP_NEW
FOR EACH ROW
DECLARE
Indice binary_integer;
BEGIN
--AUTOINCREMENTAL DEL CAMPO ID_MEDIDAS
SELECT T_MEDIDAS_TP_NEW_SEQ.NEXTVAL INTO :NEW.id_MEDIDAS_OLD FROM DUAL;
Indice:= PCK_MEDIDAS_TP.tabla_medidas_tp.COUNT+1;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede := :NEW.ID_SEDE;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_med := :NEW.ID_MEDIDAS;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN := :NEW.KWHGEN;
PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_timestamp := :NEW.TIMESTAMP;
IF :NEW.KWHGEN <0 THEN
DBMS_OUTPUT.put_line('first trigger:' ||:NEW.ID_MEDIDAS||','||:NEW.ID_SEDE||','||:NEW.TIMESTAMP);
-- INSERT INTO TEST_TRIGGER VALUES ('100', :NEW.KWHGEN, SYSDATE);
--ELSE DBMS_OUTPUT.PUT_LINE('¿?');
END IF;
END;
3.- Create a statement procedure (AFTER) where you can check your condition, in my case if kwhgen <0. If is true, I'll read the previous record in the original tbale and update the insert record with taht value.
create or replace TRIGGER D_MEDIDAS_TP_TEST_STATEMENT
AFTER INSERT ON T_MEDIDAS_TP_NEW
DECLARE
Indice binary_integer;
s_id_sede NUMBER (10,0);
s_id_med NUMBER (10,0);
s_kwhGEN NUMBER (21,2);
s_timestamp TIMESTAMP;
BEGIN
FOR Indice in 1..PCK_MEDIDAS_TP.tabla_medidas_tp.count LOOP
DBMS_OUTPUT.put_line('second trigger: kwhgen: '||PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN||', id_sede: '||PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede);
IF PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_kwhGEN <0 THEN
DBMS_OUTPUT.put_line('second trigger: v_kwhGEN is negative');
SELECT prev_KWHGEN INTO s_kwhgen
from(
SELECT LEAD (KWHGEN,1) over (ORDER BY id_medidas desc) as prev_KWHGEN
FROM T_MEDIDAS_TP_NEW WHERE ID_SEDE = PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_sede
ORDER BY id_medidas DESC) where rownum =1;
INSERT INTO TEST_TRIGGER VALUES ('100', '5555', SYSDATE);
DBMS_OUTPUT.put_line('second trigger. KWHGEN: '||s_kwhGEN);
DBMS_OUTPUT.put_line('UPDATE');
UPDATE T_MEDIDAS_TP_NEW SET KWHGEN = S_KWHGEN WHERE ID_MEDIDAS = PCK_MEDIDAS_TP.tabla_medidas_tp(Indice).v_id_med;
else DBMS_OUTPUT.put_line('¿?');
END IF;
END LOOP;
PCK_MEDIDAS_TP.tabla_medidas_tp.delete; -- vaciamos la tabla
END;