As mentioned previously, in order to use your OLAP database, you must first process the cubes that are contained within the database. Simply stated, processing the cube populates the cube definition with actual transactional data from your data warehouse or data mart. Before you actually populate your cube, however, you need to define certain optimization definitions for your cube. Analysis Services provides two primary mechanisms for optimizing the cubes within OLAP databases:
Aggregations are summaries of data that are calculated by the Analysis Server and stored in the database along with the transaction level cube data. For example, an aggregation of data would be the total sales ...