hello shinee,
RFC fm -> its mainly used to pass data from one server to another or remote server......RFC is the protocol used by SAP for remote communication.
call function 'zrfc' destination ' '.
in rfc we always pass data call by value...
update fm -> it mainly used for update work process....
when we update some value in database table we use this update fm.there is 3 types. one is V1(time critical) process another is V2(less time critical) and 3rd is collective run fm .
call function 'zupdate' in update task.
after fm you have to use commit work statement....after commit work, dialog work process end and update work process will start.
hope you know about normal fm......this is very basic question...
Thanks
Sabyasachi