Write project dictionary entries (using standards given to you by your instructor) for all the entities, attributes, and relationships shown in the E-R diagram in your answer to the Case Question. How detailed are these entries at this point? What other details still must be filled in? Are any of the entities on the E-R diagram in your answer to Case Question weak entities? Why? In particular, is the SERVICE entity type a weak entity? If so, why? If not, why not?

Case Question

Using your answer to the Case Question, 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.

Case Question

Using your answer to the Case Question, designate which attribute or attributes form the identifier for each entity type. Explain why you chose each identifier.

Case Question

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. Write an unambiguous definition for each attribute. Then, redraw PE Figure by placing the six (and additional) entities in this case on the diagram along with their associated attributes.

PE FIGURE Initial E-R for Petrie’s customer loyalty program.

Case Question

Review the data-flow diagrams given to you by your instructor. Study the data flows and data stored in these diagrams and decide whether you agree with the team’s conclusion that the only six entity types needed are listed in the case and in PE Figure. If you disagree, define additional entity types, explain why they are necessary, and modify PE Figure accordingly.

Coupon Service Promotion Customer Transaction Product