Data can be summarized by areas that are of importance to decision-makers. It helps to show weak point and strong points. It allows the users to easily see and compare different aspects or areas of their business, everything from comparing sales division performance, comparing customer information to identify where more of the business is coming from, or even in a multinational company, identify which country is creating more revenue. Typically Data Warehouses are implemented with a star schema. Star schemas consist of dimension and fact tables.
Dimension tables consist of data in which the fact tables can be reported and summarized on.
These are typically smaller parent tables. Fact tables hold the important statistical information in which business decisions can be made. The fact tables are larger than dimension tables and many of the fields are numeric and can be summarized. Dimensions help make the fact table information meaningful. Tables in the star schema are generally more de-normalized.