Analytic - Drill Down - Up
1 - About
Drilling down or up is a specific analytical technique whereby the user navigates among hierarchy levels of data ranging from the most summarized (up) to the most detailed (down)
Going up a level in the hierarchy is called drilling up the data and going down a level in the hierarchy is called drilling down the data.
In the retailer example:
- Within the time dimension, months roll up to quarters, quarters roll up to years, and years roll up to all years.
- Within the product dimension, products roll up to subcategories, subcategories roll up to categories, and categories roll up to all products.
- Within the customer dimension, customers roll up to city. Then cities roll up to state. Then states roll up to country. Then countries roll up to subregion. Finally, subregions roll up to region.
Drilling down is nothing more than adding columns from the dimension tables. Drilling up is removing them.
We can drill down or up on attributes from more than one explicit hierarchy and with attributes that are part of no hierarchy.