how to create a db2 triggers to copy one filed to another in same table before update

[ctrivino]

Hi. I am new to writing code and wanted some help or suggestions.

I am trying to write a script to put calculation results into a filed after update of item.

I tried.
CREATE TRIGGER TRA_Declared_va lue_Update
AFTER UPDATE ON TLORDER
FOR EACH ROW
MODE DB2SQL
UPDATE TLORDER set DECLARED_VALUE = ROUND((CHARGES + XCHARGES - INT_PAYABLE_AMT ),2)

and also

CREATE TRIGGER NEW_DECLARED_VA LUE
AFTER UPDATE OF DECLARED_VALUE ON TLORDER
REFERENCING NEW AS N OLD AS O
FOR EACH ROW
MODE DB2SQL
BEGIN ATOMIC
SET N.DECLARED_VALU E = ROUND((N.CHARGE S + N.XCHARGES - N.INT_PAYABLE_A MT),2);
END

they both hang system. can anyone help.