Dimensions are descriptive categories by which the numeric data (that is, measures) in a cube are separated for analysis. For example, if a cube’s measure is Production Count, and its dimensions are Time, Factory Location, and Product, users of the cube can separate Production Count into various categories of Time, Factory Location, and Product.
A dimension can be created for use in an individual cube or multiple cubes. A dimension created for an individual cube is called a private dimension. In the OLAP Manager tree view, private dimensions are found in the Dimensions folder under the cube for which they were created. A dimension that can be used by multiple cubes is called a shared dimension. They are stored in the Shared Dimensions folder in the Library folder for a database. Shared dimensions also appear in the Dimensions folders under the cubes that include them.
Shared dimensions can be used within any cube in the database. By creating shared dimensions and using them in multiple cubes, you avoid the time-consuming alternative of creating duplicate private dimensions within each of the cubes.
Shared dimensions also enable the standardization of business metrics among cubes. For example, standardized shared dimensions for time and geographical location ensure that data analyzed from different cubes will be similarly organized.
You can also create another type of dimension known as a virtual dimension. For more information, see Virtual Dimensions.