DFDs should be mechanically correct, but they should alsa accurately reflect the information system being modeled. To that end. you need to check DFDs for completeness and consistncy and draw them as if the system being modeled were timeless. You should be willing to revise DFDs several times. Complete sets of DFDs should extend to the primitive level. where every component reflects certain irreducible properties; for example, a process represents a single database operation and every data store represents