The interest-rate service cluster maintains
message exchange relationships with three types of assets: a real-estate portal consumer
(public and unidirectional relationship), an equity-loan atomic service (implied bidirectional relationship),
and an investment banking composite service (public and unidirectional relationship).
Note that the proxy atomic service serves as an intermediary that isolates the equity loan atomic
service.
MANY-TO-ONE. Sometimes the one-to-many design relationship is regarded as the many-to-one
service association. Indeed, these formats are almost identical. However, the dissimilarities typically
lie in the direction of the routed messages. Specifically, if most of the defined service
relationships are unidirectional and point to a single providing service, a different design challenge
arises.
To clarify this point, take a simple example depicted by Exhibit 12.11. The investment
portfolio atomic service is constantly being updated by three entities: the mutual funds service
cluster, the fixed-income atomic service, and the equities composite service. The illustrated
unidirectional service design relationship would obviously increase concerns about the serving
Service Cardinality 245
Real-
Estate
Portal
Consumer
Interest
Rates
Service
Cluster
Investment
Banking
Composite
Service
Equity-
Loan
Atomic
Service
Proxy
Atomic
Service
EXHIBIT 12.
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