Data, Processes, and Events: Keys to Comprehensive Analysis - High-Performance Web Databases: Design, Development, and Deployment - page 64

in INVENTORY. A backwards trace from causal events reveals the original
causal event (e.g., input or time). For example, to find the event that causes
the inventory level to be reduced (i.e., the Reduce event in INVENTORY), a
backward trace reveals that it is triggered by the Ship event in LINE ITEM.
This is in turn triggered by the Ship event in ORDER. This event is ultimately
triggered by time (i.e., the End-of-the-Day event) as is indicated in the EERD.
CONCLUSION
Analysis of the relationships between entities and the events that trigger
processes are keys to better understanding a system. There are also keys
to developing more effective tools for analysis based on events. This chapter
has illustrated how analysts can document the types of coupling in an
entity's relationships to other entities as well as the types of events expe-
rienced by the entity. More important, this chapter has demonstrated the
use of EERD. This tool can be used to relate events, data, and processes
and adds rigor to the modeling of both data and functions.