DB Trigger: select from and into current table

Question

I'm running 8.0.5 and facing a table looking like MYTAB(RECID,RECLABEL,..., PARENTRECID, PARENTRECLABEL) where:
. RECID = current record UID (say: employee number)
. RECLABEL = current record label (say: employee name)
. PARENTRECID = RECID of another record in table MYTAB (say: employee ID of the manager of the current employee)
. PARENTRECLABEL = must be made to hold automatically the contents of RECLABEL in the parent record (say: the name of the manager of the current employee)
I know an easy way to get this info would be to use a view like CREATE VIEW MYVIEW AS SELECT A.RECID, A.RECLABEL, A.PARENTRECID, B.RECLABEL "PARENTRECLABEL" FROM MYTAB A, MYTAB B WHERE A.PARENTRECID=B.RECID but for various reasons I would really love to denormalize that info into column PARENTRECLABEL using a database trigger.
Obviously, table MYTAB itself cannot be selected from during the execution of the dB trigger: mutating table error !
I tried:
. to select from a view defined as "SELECT * FROM MYTAB" as suggested in another thread, but this trick didn't seem to be sufficient to lure Oracle (it still says I'm trying to select from a mutating table !)
. to use a package within which a PL/SQL table variable is filled with the list of affected RECID on a FOR EACH ROW basis, and to issue updates in a after statement (thus: not AFTER EACH ROW) AFTER UPDATE trigger - but it's too late already and those updates are apparently not taken into account by the database.
Any other suggestions?
Thx - Didier

Answer 1

Here's the code, if the formatting in unpreserved please do let me I'll mail the same.
The Package
CREATE OR REPLACE PACKAGE save_table_package
AS
TYPE saved_test2_type
IS TABLE OF test2%ROWTYPE
INDEX BY BINARY_INTEGER;
saved_test2 saved_test2_type;
saved_test2_num NUMBER:= 1;
PROCEDURE save_test2_row(i_id NUMBER
,i_ename VARCHAR2
,i_mgr_id NUMBER
,i_mgr_ename VARCHAR2
PROCEDURE clear_rows;
END save_table_package;
show err
CREATE OR REPLACE PACKAGE BODY save_table_package AS
PROCEDURE save_test2_row(i_id NUMBER
,i_ename VARCHAR2
,i_mgr_id NUMBER
,i_mgr_ename VARCHAR2
IS
BEGIN
DBMS_OUTPUT.PUT_LINE('Enter pkg.save_test2_row:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
save_table_package.saved_test2(saved_test2_num).id := i_id;
save_table_package.saved_test2(saved_test2_num).ename := i_ename;
save_table_package.saved_test2(saved_test2_num).mgr_id := i_mgr_id;
save_table_package.saved_test2(saved_test2_num).mgr_ename := i_mgr_ename;
DBMS_OUTPUT.PUT_LINE('Saved Details Of Row ###:' | |
TO_CHAR(save_table_package.saved_test2_num,'099999') | |'('| |
TO_CHAR(save_table_package.saved_test2(saved_test2_num).id,'099') | |','| |
save_table_package.saved_test2(saved_test2_num).ename | |','| |
save_table_package.saved_test2(saved_test2_num).mgr_id | |','| |
save_table_package.saved_test2(saved_test2_num).mgr_ename | |')'
save_table_package.saved_test2_num := save_table_package.saved_test2_num + 1;
DBMS_OUTPUT.PUT_LINE('Leave pkg.save_test2_row:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
END save_test2_row;
PROCEDURE clear_rows IS
BEGIN
DBMS_OUTPUT.PUT_LINE('Enter pkg.clear_rows :'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
save_table_package.saved_test2_num := 1;
DBMS_OUTPUT.PUT_LINE(' Leave pkg.clear_rows :'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
END clear_rows;
END save_table_package;
show err
The Triggers
CREATE OR REPLACE TRIGGER trig_bfr_iup_test2_fer
BEFORE INSERT OR UPDATE OF mgr_id ON test2 FOR EACH ROW
DECLARE
BEGIN
DBMS_OUTPUT.PUT_LINE('Enter before insupd:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
save_table_package.save_test2_row(:new.id
,:new.ename
,:new.mgr_id
,:new.mgr_ename);
DBMS_OUTPUT.PUT_LINE('Leave before insupd:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
END;
show err
CREATE OR REPLACE TRIGGER trig_aft_iup_test2_stm
AFTER INSERT OR UPDATE OF mgr_id ON test2
DECLARE
BEGIN
DBMS_OUTPUT.PUT_LINE('Enter after insupd:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
FOR i IN 1 .. save_table_package.saved_test2_num - 1
LOOP
UPDATE test2 eme
SET mgr_ename = (SELECT mgr.ename
FROM test2 mgr
WHERE mgr.id = eme.mgr_id)
WHERE eme.id = save_table_package.saved_test2(i).id
DBMS_OUTPUT.PUT_LINE('MGR_ENAME Set Row#:'| |TO_CHAR(i,'099999'));
END LOOP;
save_table_package.clear_rows;
DBMS_OUTPUT.PUT_LINE('Leave after insupd:'| |TO_CHAR(save_table_package.saved_test2_num,'099999'));
END;
show err
null