Rules for Processing Each Data Record (When Adding or Changing)
If a bundle definition exists for the bundle identifier, that definition is used; otherwise, a new bundle definition is created with all data fields initialized to blanks.
The data fields in the bundle definition for which parameters were specified on the /BNDLDEF control statement are set to the values from the data record; the data fields for which no parameters were specified on the /BNDLDEF control statement remain unchanged.