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QUESTIONS AND PROBLEMS FOR REVIEW 15

Expenditure Cycle Revenue Cycle
(0, N) ,..-----------------------------,

(0, N) 1..- ......
FIGURE 1-23 Comprehensive REA Data Model for Cherokee Art and Antique Store

after an item is sold. Each purchase may not be paid in full, since items purchased from the
vendors in one transaction may not have all been sold at the same time. This is why the maxi-
mum cardinality at the "Purchase" side is many (N). Each cash disbursement (i.e., a check) can
be for one purchase or for many purchases since Jesse pays each artist or seller once per week.
In terms of the cardinalities between events and agents, as mentioned in the revenue
cycle, the general case is (l,1) at the event side and (l,N) at the agent side. In addition, in
an REA diagram, we need to illustrate each entity once only. Figure 1-22 shows the
completed REA diagram for Cherokee's expenditure cycle.
Finally, to make a comprehensive data model for Cherokee, we combine the revenue
and expenditure cycle processes as illustrated in the REA diagram in Figure 1-23.

KEY TERMS

entity duality economic events
relationship entity-relationship diagram (ERD) economic agents
cardinality REA data model
data modeling economic resources

QUESTIONS AND PROBLEMS FOR REVIEW

MULTIPLE-CHOICE QUESTIONS

1.1 Which of the following is considered an entity in an REA data model?
(a) Customer
(b) Sale
(c) Finished goods
(d) All of the above are correct.