The rules for creating DFDs.

Part 1 1. Describe the rules for creating DFDs.

  1. 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.
  2. Pretend you are Michael or Adam and are asked to review the order system context diagram shown on Figure 1, and compare it with the order system diagram 0 DFD shown on Figure 2. 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) Explain the importance of leveling and balancing (e) Could the data store have been shown in the context diagram? Why or why not? Part 2
    Part 2. Cheapest College Driver Insurance Background The company uses several factors to set discounts, as follows: • A student who has taken a safe driver course earns a 5% discount. • A student with a clean record (no tickets or accidents in the last three years) earns a 5% discount. • A student who is 23 or older earns a 5% discount • A student who meets all three conditions (has taken a safe driver course and has a clean record and is 23) earns an additional bonus discount of 5%.
    Tasks 1. Create a decision table that describes the discount rules. 2. Draw a simplified decision tree that shows the discount rules. 3. What are the pros and cons of using a decision table versus a decision tree