IBM plsql - cursor - sql

Question

I am new with PLSQL (IDM db2) and I am trying to create a procedure to find and delete some admin_tasks if they exist.
Explanation:
By running the bellow query1, I can find out the list of tasks in the scheduler:
SELECT * FROM SYSTOOLS.ADMIN_TASK_LIST;
To delete the task, I can run this query2:
call sysproc.admin_task_remove('TASK_NAME', null);
So I want to create a procedure to delete all tasks with the pattern "My_Task_*".
This should delete all the tasks with that pattern and leave the other existent tasks intact. The procedure should handle cases where the admin_tasks doesn't exist, or no admin_tasks were ever created, and should run without throwing any errors.
I have researched and found out that this can be made using cursors.
Can you help me to implement this?
EDIT:
I managed to find this solution:
BEGIN
FOR v1 AS c1 CURSOR FOR
SELECT NAME
FROM SYSTOOLS.ADMIN_TASK_LIST
WHERE NAME LIKE 'My\_task\_%' ESCAPE '\'
DO
call sysproc.admin_task_remove(NAME, null);
END FOR;
END
This seems to work except if the SYSTOOLS.ADMIN_TASK_LIST was not yet defined.
If it's not defined than I get this error when I run the query: If it is not defined I get this error
: [Code: -204, SQL State: 42704]
"SYSTOOLS.ADMIN_TASK_LIST" is an undefined name.. SQLCODE=-204,
SQLSTATE=42704, DRIVER=4.25.1301
So how can I bypass this error? DOing something like first checking if SYSTOOLS.ADMIN_TASK_LIST is defined, if its defined to the above query if not do nothing.

Answer 1

Presuming that your client tool uses '#' as a statement delimiter.
BEGIN
FOR L1 AS
SELECT NAME
FROM SYSTOOLS.ADMIN_TASK_LIST
WHERE NAME LIKE 'My\_task\_%' ESCAPE '\'
DO
CALL ADMIN_TASK_REMOVE (L1.NAME, NULL);
END FOR;
END
Update:
With error handling for non-existing table. The error handler just "eats" the error on non-existing table use.
You must use dynamic sql for that.
BEGIN
DECLARE SQLSTATE CHAR (5);
DECLARE L_NAME VARCHAR (128);
DECLARE C1 CURSOR FOR S1;
DECLARE EXIT HANDLER FOR SQLSTATE '42704' BEGIN END;
PREPARE S1 FROM
'
SELECT NAME
FROM SYSTOOLS.ADMIN_TASK_LIST
WHERE NAME LIKE ''My\_task\_%'' ESCAPE ''\''
';
OPEN C1;
L1:
LOOP
FETCH C1 INTO L_NAME;
IF SQLSTATE = '02000' THEN LEAVE L1; END IF;
CALL ADMIN_TASK_REMOVE (L_NAME, NULL);
END LOOP L1;
CLOSE C1;
END