11. The computer readable storage medium of claim 7 , wherein at least one of the first and second levels additionally references a third data source.
7. A computer readable storage medium, comprising executable instructions to: receive an abstract query specifying first and second levels in a multiple source hierarchical dimension, wherein the first level references a primary first data source, and the second level references a primary second data source; generate a first data source specific query specifying the first level for the first data source; execute the first data source specific query against the first data source to produce results for the first level, wherein the results for the first level include a value for the first level; generate a context expression for the second data source, wherein the context expression relates the first level to the second level; generate a second data source specific query specifying the second level and including the context expression for the second data source; execute the second data source specific query against the second data source to produce results for the second level; and return the results for the first and second levels.