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 Question 1. 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.
1. PROMOTION_ID- PROMOTION CODE PROVIDED BY COMPANY
2. PROMOTION_AMOUNT- PROMOTION AMOUNT FOR THE CODE
1. AMT_POINTS- THE AMOUNT OF POINTS THE CLIENT HAS
2. COUPON_ID DISCOUNT CODE OFFERED BY THE COMPANY
1.ONLINE_NAME- LOG IN OR USER NAME
2.CUSTOMER_NUMBER- REWARDS CARD NUMBER FOR IN STORE SHOPPERS
1.SERVICE_ID- SERVICE IDENTIFIER FOR SERVICE RENDERED
2.STORE_JOB- -STORE PROVIDING SERVICES
1. TRANSACTION ID- ID FOR TRANSACTION TYPE
2. TRANSACTION_TYPE_ TYPE OF TRANSACTION BEING PRERFORMED
1.PRODUCT_ID- PRODUCT NAME
2. PRODUCT_QUANTITY-AMOUNT OF PRODUCTS NEEDED
3.Using your answer to Question 2, designate which attribute or attributes form the identifier for each entity type. Explain why you chose each identifier.
4. Using your answer to Question 3, draw the relationships between entity types needed by the system. Remember, a relationship is needed only if the system wants data about associated entity instances. Give a meaningful name to each relationship. Specify cardinalities for each relationship and explain how you decided on each minimum and maximum cardinality at each end of each relationship. State any assumptions you made if the Petrie s Electronics cases you have read so far and the answers to questions in these cases do not provide the evidence to justify the cardinalities you choose. Redraw your final E-R diagram in Microsoft Visio.
Petrie’s Electronics Case, Chapter 7, Questions 1–5 and 7 CASE: PETRIE’S ELECTRONICS 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 in 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], along with a description of the major entities.” “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 I’ll let you know if I 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), just in 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…