By Herbert J. Bernstein

© Copyright 2000, 2002 Herbert J. Bernstein

Process Modeling is an aspect of business system modeling which focuses on the flows of information and flows of control through a system. The graphical aspects of process modelling have evolved from classic Flowcharting techniques. The major difference between data modeling and process modeling is that in the former we concentrate on what information is moved and where it is moved, while in the later we focus on how it is moved and when it is moved

• Data Flow Diagram
  • Modern version of a systems flowcharts
  • Focus on the data flows, not the flow of control
  • Process: rounded rectangle
  • External agent: rectangle with square corners
  • Data stores: open-ended rectangles
• Processes
  • Processes transform information
  • The state of system is information
  • Processes are systems
  • Systems are processes
  • Described by programs, decision tables, program flowcharts
• Event-driven models
  • Decompositions based on events and the systems that respond to those events
  • Context diagram -- initial top level overview of the system with boundary transactions
  • Function decomposition -- breakdown into subsystems
  • Subsystem context diagrams may be further decomposed
  • Event-response lists -- entity relationship model based on events
  • Event diagram -- flow for a single event
  • System diagram -- operational overview of the system with boundary transactions
  • Detailed (primitive) diagram -- fully detailed diagram
    • Initially supported by verbal descriptions
    • Final implementation requires programs, policies, procedures