Structuring Systems Requirements: Conceptual Data Modeling Jim Watanabe, manager of the "No Customer Escapes" project and assistant director of IT for Petrie's Electronics, was sitting in the company cafeteria. He had just finished his house salad and was about to go back to his office when Stephanie Welch sat down at his table. Jim had met Stephanie once, back when he started work at Petrie's. He remembered she worked for the database administrator. "Hi, Jim, remember me?" she asked. "Sure, Stephanie, how are you? How are things database land?" "Can't complain. Sanjay asked me to talk to you about the database needs for your new customer loyalty system." Stephanie's phone binged. She pulled it out of her oversize bag and looked at it. She started to text as she continued to talk to Jim. "How far along are you on your database requirements?" That's kinda rude, Jim thought. Oh well. "We are still in the early stages. I can send you a very preliminary E-R diagram we have [PE Figure 7-1 D), along with a description of the major entities." Coupon Service Promotion Customer Transaction Product PE FIGURE 7-1 Initial E-R for Petrie's customer loyalty program. "OK, that will help. I suspect that you won't have too many new entities to add to what's already in the system," Stephanie responded, still looking at her phone and still texting. She briefly looked up at Jim and smiled slightly before going back to texting. "Just send the E-R to me, and l'll let you know if have any questions." She stood up, still looking at her phone. "Gotta go," she said, and she walked away. OK, Jim thought, I need to remember to send Stephanie the preliminary E-R we have. I should probably send her the entity descriptions too (PE Table 7-1 O), just case. Jim stood up, carried his tray over to the recycling area of the cafeteria, and went back to his office. When Jim got back to his office, Sanjay was waiting for him. "I've got more information on those alternatives we talked about earlier," Sanjay said. "I had one of my employees gather some data on how the alternatives might satisfy our needs." (See the descriptions of the alternatives in PE Table 5-20.) Sanjay handed Jim a short report. "The matrix shows the requirements and constraints for each alternative and makes it relatively easy to compare them." (See PE Figure 7-2 0.) "The matrix favors the XRA CRM system," Jim said, after looking over the report. "It looks like their proposal meets our requirements the best, but the Nova group's proposal does the best job with the constraints."
7-49. Again, review the DFDs you developed for the Petrie’s Electronics case (or those given to you by your instructor). Use these DFDs to identify the attributes of each of the six entities listed in this case plus any additional entities identified in your answer to Case Question 7-48. Write an unambiguous definition for each attribute. Then, redraw PE Figure 7-1 by placing the six (and additional) entities in this case on the diagram along with their associated attributes
Solution:
Attributes
Every thing/business can be defined and identified using a set of (features/ qualities/ traits) or properties. A set of properties are common to every instance of the thing/business and are commonly called as attributes. A common standard/syntax is followed for writing an attribute in this book. While naming an attribute, all nouns are written with initial capitalization followed by lower case letters.
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