A Hierarchy is a systematic way of organizing the Members of a Dimension into a logical tree structure that defines parent-child Aggregation relationships, where Parent Members, i.e., Aggregate Members, correspond to the consolidation of Child Members. By arranging Members of a Dimension into a Hierarchy, not only can the OLAP model calculate the aggregation of Dimension Members, but also mathematical calculations in the form of Cube Formulas can be eliminated since the values for the Child Members will automatically sum up or total to a Parent Member.
