When posting the IDoc segments, process the first field (MSGFN) in each segment to determine the function to be performed for the segment: 009 for add, 004 for change, 003 for delete, 018 for unchanged data and 005 for a refresh function.

For functions 009, 004, 018, and 005, the data must be added to the receiving system (if not already available) or changed (if it already exists in the receiving system).

For function 003, the data must be deleted in the receiving system.

For master data with reducible message types you must not change the field in the database if the corresponding IDoc segment field has the contents "/".

When master data is posted, master data objects can be assigned to a class using the function module CACL_OBJECT_ALLOCATION_MAINT.