Data warehousing  What is cube grouping?
What is cube grouping? A transformer built set of similar cubes is known as cube grouping.
 A single level in one dimension of the model is related with each cube group.
 Cube groups are generally used in creating smaller cubes that are based on the data in the level of dimension.
 CUBE takes a specified set of grouping columns and creates subtotals for all of their possible combinations.
 CUBE generates all the subtotals that could be calculated for a data cube with the specified dimensions in a multidimensional analysis.
 If the specification of a CUBE(time, region, department), then the result set will include all the values that would be included in an equivalent ROLLUP statement plus additional combinations.  CUBE can be helpful in generating summary tables.
 It is typically most suitable in queries that use columns from multiple dimensions rather than columns representing different levels of a single dimension.
 For instance, a commonly requested crosstabulation might need subtotals for all the combinations of month, state, and product.
 These are three independent dimensions, and analysis of all possible subtotal combinations is commonplace.
 In contrast, a crosstabulation showing all possible combinations of year, month, and day would have several values of limited interest, because there is a natural hierarchy in the time dimension.
 Subtotals such as profit by day of month summed across year would be unnecessary in most analysis.
