Chapter 4. Data modeling: End to end 87
4.2.2 Define the granularity
Stage two of the process is to determine the right level of detail that must be
contained within the model and ultimately, within the fact table. As an example, a
model might contain a complete record of a sales transaction as one entry within
the fact table, with all the products sold contained within the one entry or maybe
not even listed. In this case, the lowest level is be the individual sales transaction.
An alternative can be to set the product as the lowest level, thus requiring
multiple entries within the fact table to represent just one sales transaction. The
grain (detail) of the fact table has a significant impact on the data warehouse
from business, technical, ...