Granularity
A fact table is usually designed at a low level of Granularity. This means that we need to find the lowest level of information that can store in a fact table.
E.g. Employee performance is a very high level of granularity. Employee_performance_daily, employee_perfomance_weekly can be considered lower levels of granularity.
Granularity should be determined at database design level, because changes can be challenging later on.
changes involve a few steps;
- change structure of fact table
- possible changes in dimension tables
- changes in data loading
- changes in data querying
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