Mutating table error

[mooks]

Hi

I have encountered a mutating table error while updating a table as shown below.
Oracle error encountered : ORA-04091 Mutating Table....
May I know how to solve this problem since I am already using the workaround fro mutating table... what is wrong? Please help, thanks!



CREATE OR REPLACE PACKAGE pkg_students AS
TYPE t_student_id IS TABLE OF students.student_id%TYPE
INDEX BY BINARY_INTEGER;
TYPE t_exam_id IS TABLE OF students.exam_id%TYPE
INDEX BY BINARY_INTEGER;
TYPE t_datetime IS TABLE OF students.datetime%TYPE
INDEX BY BINARY_INTEGER;

v_student_id t_student_id;
v_exam_id t_exam_id;
v_datetime t_datetime;
v_num BINARY_INTEGER := 0;

END pkg_students;
/

CREATE OR REPLACE TRIGGER R_student_trigger
BEFORE INSERT OR UPDATE ON students
FOR EACH ROW
BEGIN
pkg_students.v_num := pkg_students.v_num + 1;
pkg_students.v_student_id(pkg_students.v_num) := :new.student_id;
pkg_studentsl.v_exam_id(pkg_students.v_num) := :new.exam_id;
pkg_students.v_datetime(pkg_students.v_num) := :new.datetime;

END R_student_trigger;
/

CREATE OR REPLACE TRIGGER S_student_trigger
AFTER INSERT OR UPDATE ON students
DECLARE
s_student_id students.student_id%TYPE;
s_exam_id students.exam_id%TYPE;
s_datetime students.datetime%TYPE;
BEGIN

FOR v_loopindex IN 1..pkg_students.v_num LOOP
s_student_id := pkg_students.v_student_id(v_loopindex);
s_exam_id := pkg_students.v_exam_id(v_loopindex);
s_datetime := pkg_students.v_datetime(v_loopindex);

dbms_output.put_line(pkg_students.v_student_id(v_loopindex));

END LOOP;

pkg_students.v_num := 0;

END S_student_trigger;
/

[Shestakov]

First question: Is this code is real code or not?
I dot'n' see no any problems with mutating tables.
Then :
because u don't select no 1 row from students table why u need
use techology with BEFORE UPDATE (ROW) trigger and
AFTER UPDATE (STATMENT) trigger and package specification
as "common memory"?

[Edited by Shestakov on 07-16-2002 at 02:23 AM]

[mooks]

Yes these codes are real except for the naming. There is a delete cascade on students table but I still do not know why is there a mutating error. Any help please?