Chapter 7: Structuring System Process Requirements Jim and Sanjay chatted in Jim's office while they waited for Sally to arrive. "Good work on researching those alternatives," Jim said. "Thanks," replied Sanjay. "There are a lot of alternatives out there. I think we found the best three, considering what we are able to pay." Just then Sally walked in. "Sorry I'm late. Things are get- ting really busy in Marketing right now. I've been putting out fires all morning." Sally sat down at the table across from Jim. "I understand," Jim said. "But to stay on schedule, we need to start focusing on the specifics of what we want our system to do. Remember when you wanted more details on what the system would do? Well, now we start to spend some serious energy on getting that done." "Awesome," replied Sally, as she pulled a Red Bull out of her oversized bag and popped it open. "I've got a list here of four core functions the system must perform," said Sanjay, pulling copies of a list from a folder on the table (PE Table 7-1). "Let's look at these." After reviewing the list Sanjay had given them, Jim said, "Nice job, Sanjay. But we need to put this in graphical for- mat, so that everyone can see what the inputs and outputs are for each function and how they are related to each other. We also need to see how the new system fits in with our existing data sources. We need ..." "Some data flow diagrams," Sanjay interrupted. "Exactly," said Jim. "They are already done," replied Sanjay, handing dia- grams to both Jim and Sally. "I've already created a first draft of the context diagram (PE Figure 7-1) and a level-1 diagram (PE Figure 7-2). You can see how I've defined the boundaries of our system, and I've included our existing product and marketing databases." "What can I say?" Jim said. "Again, a nice job on your part. These diagrams are both good places for us to start. Let's get copies of all of this to the team." "I'll be right back," Sally said, standing up. "I need to get some coffee." PE TABLE 7-1 Function Record customer activities Send promotions Generate point redemption coupons Four Core Functions of Petrie's Customer Loyalty System Description When a customer makes a purchase, the transaction must be recorded in the customer loyalty system, as the r the system generates are driven by e Generate customer reports a rewards customer purchases. Similarly, when a uses a coupon generated by the system, it must also be recorded, so that the customer activity records can be updated to show that the coupon has been used and is now invalid. Data about customer activities provide information about what types of products customers tend to buy and in what quantities. This information helps determine what sales promotion materials are best targeted at what customers. Customers who buy lots of video games should receive promo- tions about games, game platforms, and HD TVs, for example. Data about customer activities is used to generate coupons for future purchases Those coupons must be made avail- able to customers, either as paper coupons sent in the mail or online, in the customer's private account area. Once created, the customer activity database needs to be updated to sho the creation of the coupon. The loyalt points needed to create the coupon must be deducted from the customer total points. From time to time, either in the mail or electronically, customers need to be sent account reports that show their recent purchases, the coupons they have been issued that have not yet been redeerned, and the total points they have amassed from their purchases. STRUCTURING SYSTEM PROCESS REQUIREMENTS 241 PE FIGURE 7.1 Context diagram CHAPTER 7 Purchases Customer Coupons No Customer Escapes System Reports Tailored Promotions Coupons Customer tea Coupons Customer Purchases Record Customer Activities Transactions Customer Activity Records Promotions Customer Activities Marketing Database Sendi Promotions Coupon Info Customer Activities Customer Activity Info Tailored Promotions Generate Point Redemption Coupons Coupons Customer Generate Reports Customer Reports Product Info Product Database getsubout PE FIGURE 7-2 Level-1 DFD Case Questions 7.57 Are the DFDs in PE Figures 7-1 and 7-2 balanced? Show that they are or are not. If they are not hal- anced, how can they be fixed? 7.58 Decompose each of the core processes in PE Figure 7-2 and draw a new DFD for each core process. 7.59 Has the team overlooked any core processes in the system that should be in PE Table 7-1 and PE Figure 7-2? What would they be? Add them to PE Table 7-1 and PE Figure 7-2. 7.60 Redesign PE Figures 7-1 and 7-2 so that they are easier to understand, more efficient, and more comprehensive 7.61 Why is it important for the team to create DFDs if they are not going to write the actual system code themselves?