My first Publication Agile-Data-Warehouse-Design-eBook | Page 129

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Chapter 4
Remember, this question is designed to focus the stakeholders on identifying the
responsible subject (who) and object (what) of the event, to model its atomic-level
detail. If stakeholders respond with:
Warehouse worker ships product.
Add the next event
and any new
dimensions. Tick off
its conformed
dimensions
You add this new main clause to the matrix below CUSTOMER ORDERS, as in
Figure 4-9, leaving enough room to add an event name later. You then check the
dimension columns to see if the new subject (WAREHOUSE WORKER) and
object (PRODUCT) are potential conformed dimensions. PRODUCT is already on
the matrix so you should tick its use on the new event row, once you have con-
firmed that stakeholders are talking about the same products described in the same
way as before. Though it seems unlikely, you should also confirm that shipping
does not create new products otherwise you would use a * instead of a tick.
Figure 4-9
Adding “warehouse
worker ships
product” to the
event matrix
Role-Playing Dimensions
Check each new
dimension for
synonyms among
the dimensions
already on the
matrix
WAREHOUSE WORKER looks like a new dimension but before you add it you
should check if it is a synonym for an existing dimension; W-type can help you
here. WAREHOUSE WORKER is a who, and there are already two other whos:
CUSTOMER and SALESPERSON. Are either of these similar to warehouse work-
ers? Customers obviously aren’t but warehouse workers and salespeople, while
they’re not the same people, they maybe a specific type of who: employees of the
same organization. If so, they would share many common attributes (e.g., Em-
ployee ID, Department, Hire Date, etc.) and could be modeled as a single role-
playing conformed dimension. You should confirm with stakeholders:
Are warehouse workers and salespeople employees?