My first Publication Agile-Data-Warehouse-Design-eBook | Page 77

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Chapter 2
Before naming an
event you may need
to change its subject
its details to establish a better subject and/or event name. For example, the event
“‘SALESPERSON sells PRODUCT to DISTRIBUTOR”’ might be reordered as
“‘DISTRIBUTOR orders PRODUCT from SALESPERSON”’ and named
DISTRIBUTOR ORDERS rather than SALESPERSON SALES. The initial subject
(SALESPERSON) has helped to tease out the event stories, but its work here as a
subject is now done.
If the subject-verb combination doesn’t provide a good event name try using the
object and a how detail.
Completing the Event Documentation
Add the story type
to the table heading
after the event
name
Finally, now that you have all the event details you can define the story type with
confidence. To recap, if the event has a when detail with an every preposition it is
recurring. If the event has multiple when details that can change it is evolving.
Otherwise it is a discrete event. You record the story type using one of the table
codes: DE, RE, or EE which you place in the event name header. Table level codes
follow the table name within square brackets as in Figure 2-13.
[DE] : Discrete event
[RE] : Recurring event
[EE] : Evolving event
Draw a double bar
on the right edge to
denote a completed
table
The finished stories
can now be told
When you finish documenting an event using a spreadsheet (as in Figure 2-13)
draw a double bar on the right edge to signify that the table is complete (for now).
This is a helpful visual clue because BEAM ✲ tables grow wider than the screen or
printed page. If you can’t see the double bar you know you should scroll right or
look for a continuation page to see more details.
By scanning the completed table stakeholders can now read their finished event
stories, such as:
Elvis Priestly (is that really his name?) orders 1 iPip Blue Suede on the 18 th May
2011, for delivery due on the 22 nd May 2011, from James Bond at the POMStore
NYC, for delivery to Memphis, TN, for $249, on no promotion with zero dis-
count, using ORD1234.
Vespa Lynd orders a POMBook Air on the 29 June 2011, for delivery on the 4th
July 2011, from POMStore.com, for delivery to London, UK, for £1,400 with a
launch event 10% discount, using ORD007.
With a little tweaking of prepositions and reordering of details (mainly the how
manys) you can now construct an event story archetype for CUSTOMER ORDERS
from the examples. This final piece of documentation might say: