You can implement an exit function module to:
Define additional mapping rules if the standard mapping and conversion rules do not support your requirements (for outgoing and incoming files)
You can also select data from additional database tables not included in the standard selection step (such as customer database tables) and therefore not made available in the source/target field inventory . The exit module can, however, use the same source/target fields as the standard mapping rules.
Define additional file checks (for incoming files only)
You have already created the function module you want to implement in the format tree.
Note
You write ABAP source code in the ABAP Workbench – not in the DME Engine.
To create your exit module, you can use the following template function modules:
Outgoing: DMEE_EXIT_TEMPLATE or DMEE_EXIT_TEMPLATE_EXTENDED
Incoming: DMEE_EXIT_TEMPLATE_IN_MAPPING
Outgoing Files
You can specify exit modules for elements and atoms. When you create one of these nodes, select the mapping procedure Exit module . On the Source tab, you then enter the name of the exit function.
Incoming Files
You can specify exit modules for elements, action nodes, and technical nodes. For use in mapping rules, enter the exit module on the Mapping tab and select the corresponding radio button. For use in file checks, enter the exit module on the File Checks tab.