The no data indicator just says that you want the BDC to skip that field. Also, you need to use the no data indicator if there is a field on the screen for some transactions but not others. If you do not use the no data indicator on the transactions where the field doesn't exist the BDC will error out the transaction.
To use the no data indicator just put a / or whatever character you choose in the first byte of the field.
no data indicator is for mapping / migration-programs to fill file for SAP-interfaces like rfbibl00 or rfbikr00.
These programs need that info to realize that a field is out of scope.
if you programming your own bdc - it's not necessary to fill fields with no data!
Message was edited by: Andreas Mann