Error: ORA-04084: cannot change NEW values for this trigger type

Cause: New trigger variables can only be changed in before row insert or update triggers.

Action: Change the trigger type or remove the variable reference.

Example:

create table a(id number,ROWCHANGEDATE date);

CREATE OR REPLACE TRIGGER a_UPDATE
   AFTER UPDATE ON a
   REFERENCING NEW AS NEW OLD AS OLD
   FOR EACH ROW
BEGIN
            :NEW.ROWCHANGEDATE:=sysdate;
END;
/

ERROR at line 1:

ORA-04084: cannot change NEW values for this trigger type

 

Change the trigger type from after to before:

CREATE OR REPLACE TRIGGER a_UPDATE
   BEFORE UPDATE ON a
   REFERENCING NEW AS NEW OLD AS OLD
   FOR EACH ROW
BEGIN
            :NEW.ROWCHANGEDATE:=sysdate;
END;
/

Trigger created.