I'm a little confused - the QTEMP library is just that, a temporary library, so any files in it are surely only being used as work files for the current job. As soon as the job completes, the contents of the QTEMP library will be removed.
Having said that, there is no reason why you cannot add a trigger to a file in QTEMP the same as you can to any database file in any library.
The following worked on my box:
The only prerequisites being that a) the file existed in my jobs QTEMP, and b) the trigger program being called also existed.
Also, bear in mind that each job has its own QTEMP which is not generally accessible by other jobs.
Hope this helps
no, you can not. A trigger is a program runned by DB2 for you