Atomic Transaction with nested BEFORE INSERT/UPDATE Triggers - database

Question

Currently i am implementing a procedure, which creates a couple of rows in some related tables out of a template. So my Procedure consists of a SAVEPOINT followed by some INSERT statements on different tables, and a Cursor to insert some more rows to other tables while referencing on the newly created primary keys.
Each of those tables has an BEFORE INSERT/UPDATE trigger defined which has the purpose to:
Get a new primary key from a sequencer if it is not defined in the INSERT statement (there are cases where I need to set the Primary key explicitely to reference it later on in the same transaction)
Set some default values if they are NULL
Set auditing fields (last_change_date, last_change_user, etc..)
The transaction fails with ORA-04091: table is mutating, trigger/function may not see it
I am understanding, that I could Workaround this, by declaring PRAGMA AUTONOMOUS TRANSACTION in each Trigger, but my Transaction would not be atomic any more then, as it is the requirement that all those datasets should be created/inserted as a whole or None of them.
So what am I doing wrong in the design of my database?
UPDATE: This is the Code of the trigger
CREATE TRIGGER TRG_AUFTRAG_B_IU
BEFORE INSERT OR UPDATE
ON AUFTRAG
FOR EACH ROW
BEGIN
IF INSERTING THEN
IF :new.id is NULL or :new.id = 0 THEN
SELECT SEQ_AUFTRAG.nextval into :new.id from dual;
END IF;
IF :new.nummer is NULL or :new.nummer = 0 THEN
SELECT nvl(MAX(NUMMER),0)+1 INTO :new.nummer FROM AUFTRAG WHERE EXTRACT(YEAR from DATUM) = EXTRACT(YEAR from :new.DATUM);
END IF;
--DEFAULT Values
IF :new.BETR_GRENZWERTE_RELEVANT is NULL THEN
SELECT 0 INTO :new.BETR_GRENZWERTE_RELEVANT FROM dual;
END IF;
IF :new.DOKUMENTE_ABGELEGT is NULL THEN
SELECT 0 INTO :new.DOKUMENTE_ABGELEGT FROM dual;
END IF;
IF :new.EXT_ORG is NULL or :new.EXT_ORG < 1 THEN
SELECT 1 INTO :new.EXT_ORG FROM dual;
END IF;
:new.ERSTELLT_VON := nvl(:new.ERSTELLT_VON,user);
:new.ERSTELLT_DATUM := nvl(:new.ERSTELLT_DATUM,sysdate);
END IF;
:new.GEAENDERT_VON := user;
:new.GEAENDERT_DATUM := sysdate;
END;

Answer 1

You can write it more compact like this:
CREATE TRIGGER TRG_AUFTRAG_B_IU
BEFORE INSERT OR UPDATE
ON AUFTRAG
FOR EACH ROW
BEGIN
IF INSERTING THEN
:new.id = NVL(NULLIF(:new.id, 0), SEQ_AUFTRAG.nextval);
--DEFAULT Values
:new.BETR_GRENZWERTE_RELEVANT := NVL(:new.BETR_GRENZWERTE_RELEVANT, 0);
:new.DOKUMENTE_ABGELEGT := NVL(:new.DOKUMENTE_ABGELEGT, 0);
IF :new.EXT_ORG is NULL or :new.EXT_ORG < 1 THEN
:new.EXT_ORG := 1;
END IF;
:new.ERSTELLT_VON := nvl(:new.ERSTELLT_VON,user);
:new.ERSTELLT_DATUM := nvl(:new.ERSTELLT_DATUM,sysdate);
END IF;
:new.GEAENDERT_VON := user;
:new.GEAENDERT_DATUM := sysdate;
END;
Only "problem" is this part
IF :new.nummer is NULL or :new.nummer = 0 THEN
SELECT nvl(MAX(NUMMER),0)+1 INTO :new.nummer
FROM AUFTRAG
WHERE EXTRACT(YEAR from DATUM) = EXTRACT(YEAR from :new.DATUM);
END IF;
This one you should put into your procedure or in a statement trigger (i.e. without FOR EACH ROW clause) like this:
CREATE TRIGGER TRG_AUFTRAG_B_A
AFTER INSERT ON AUFTRAG
BEGIN
UPDATE
(SELECT ID, NUMMER,
ROW_NUMBER() OVER (PARTITION BY EXTRACT(YEAR from DATUM) ORDER BY ID) as N
FROM AUFTRAG)
SET NUMMER = N
WHERE NUMMER IS NULL;
END;