The purpose of Microsoft® SQL Server™ OLAP Services is to provide rapid analytical access to data warehouse data. To accomplish this purpose OLAP Services creates multidimensional cubes from data in the data warehouse fact and dimension tables. Numerical measures are also summarized into preaggregated values during cube construction. Cubes are stored in multidimensional structures that are designed for rapid query response, combining preaggregated information with raw fact data to respond to a wide variety of queries.
Cubes can contain data summarized, copied, or read directly from the data warehouse. Changes to the structure of the data warehouse or the data contained in it can affect the integrity and accuracy of cubes that have been created from the data warehouse. Because OLAP Services provides continuous online access to cubes, changes to the underlying data warehouse must be approached with a clear understanding of their effects on cubes and how to manage the synchronization of data in the data warehouse with data in cubes.