Oracle^® Business Intelligence Server Administration Guide > Creating and Administering the Business Model and Mapping Layer in an Oracle BI Repository >

About Dimensions and Hierarchical Levels

In a business model, a dimension represents a hierarchical organization of logical columns (attributes) belonging to a single logical dimension table. Common dimensions might be time periods, products, markets, customers, suppliers, promotion conditions, raw materials, manufacturing plants, transportation methods, media types, and time of day. Dimensions exist in the Business Model and Mapping (logical) layer and are not visible to end users.

In each dimension, you organize attributes into hierarchical levels. These logical levels represent the organizational rules, and reporting needs required by your business. They provide the structure (metadata) that the Oracle BI Server uses to drill into and across dimensions to get more detailed views of the data.

Dimension hierarchical levels are used to perform the following actions:

• Set up aggregate navigation
• Configure level-based measure calculations (refer to Level-Based Measure Calculations Example)
• Determine what attributes appear when Oracle BI Presentation Services users drill down in their data requests