My first Publication Agile-Data-Warehouse-Design-eBook | Page 60

Modeling Business Events
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Example data clarifies the meaning of each event detail as you discover it with
the minimum documentation.
Examples avoid abstraction. Stakeholders can start to visualize how their data
might appear on reports.
Examples demonstrate how events behave over time by illustrating typical,
exceptional, old, new, minimum, and maximum values amongst other event
stories.
Capturing examples quickly leads to an understanding of the story type, and
eventually to a definition of the event granularity (the set of detail values that
uniquely identify each event story).
Wait until you have at least one when detail before collecting example data.
Having a when detail helps you get more interesting examples that tell a story.
Event Story Themes
To model events rapidly you want to describe each detail as fully as possible using
the minimum number of example stories. You can discover and document most of
what you need to know in five or six example rows by asking for stories that
illustrate the following five themes:
Useful event stories
follow five themes
Typical
Different
Repeat
Missing
Group
Figure 2-5 shows how the themes vary slightly across the 7Ws. The italic descrip-
tions suggest the range of values that you want to illustrate for each “W” (by using
the typical and different themes). Armed with this information you are now ready
to start “modeling by example”: asking the stakeholders to tell you event stories for
each theme.
Themes help you
discover data ranges
for each
of the 7Ws
Figure 2-5
Story theme
template