1. Describe the rules for creating DFDs.
2. What are the data flow and process combinations that must be avoided when creating a DFD?
3. Explain what a diagram 0 is and how it is used.
4. Ask Michelle and Aidan to review the order system context diagram on page 192, and compare it with the order system diagram 0 DFD on page 196. Then ask them to answer the following questions:
(a) How many external entities are shown in each diagram?
(b) In each diagram, how many data flows connect to the external entities?
(c) How many processes are identified in the diagram 0 DFD?
(d) Could the data store have been shown in the context diagram? Why or why not?

You are a senior systems analyst at Globe Consulting, a growing IT consulting firm. You are leading the development team for a major client. You need to explain data and process modeling to your two newly hired junior analysts (Michelle and Aidan) before meeting with the client tomorrow afternoon.