Data Flow Oriented Design III
(for transaction DFD)
Step 4: Identify the transaction center and the flow characteristics of
each action path
Step 5: Map the transaction flow into a structure that contains a
reception branch and a dispatch center
Step 6: Perform second level factoring by moving "outward" from
transform center on DFD. Develop incoming, transformation, and outgoing
segments of the structure separately
Step 7: Refine each sub-structure using software concepts and design
guidelines:
- coupling
- cohesion
- explosion/implosion
- scope of effect/control
- common sense