Chapter 7 Petrie

1. The two DFD’s in Petrie Electronics Case Study depicted in Figure 7-1 and Figure 7-2 are not balanced. In the context diagram, there are two inputs from the customer source and three outputs to the customer sink. In the Level-1 DFD, this is depicted the same with one exception. There is an additional input coming from the Marketing Database, providing promotions to the send promotions process. This is an additional input that is causing the DFD to be unbalanced. To make the DFD balanced, one would simply need to add the additional input to the context diagram.

2. See Figure 1.1 Below.

3. The team has covered all of the functions of the customer loyalty system. They include a process for recording customer activities, a process for sending promotions, and a process to generate point redemption coupons and customer reports.
5. The team should create DFDs to show what they need the actual personnel who will write the code to do. The DFDs are like a blue print for building a house. Architects just design and draw the blue prints out. They do not build the house. The construction workers build the house based off of the blue prints. Otherwise, the construction crew would not have any idea what to build. The same concept exists in this scenario, and that is why even though the team is not writing the code themselves, they still need a DFD drawn to show what their requirements are.

Figure 1.1

USE-CASE DIAGRAM (Send Promotions)

KITE-LEVEL USE-CASE (Send Promotions)

USE-CASE TITLE: Send promotions
PRIMARY ACTOR: Customer, marketing database, customer activity records
LEVEL: Kite (summary)
STAKEHOLDERS: Customers, Marketing (Database)
PRECONDITION: Customer Activities Earn Points
MINIMAL GUARANTEE: Points total earned do not meet minimum requirements for promotion.
SUCCESS