In ForecastingApp data is organized in model cubes - massive tables with uniform layout and cube can hold billions or hundreds of billions data points.
Each dimension has one or more elements which can be organized into hierarchies. In this way you can easily navigate from details to summary and vice versa. The cube automatically takes care of correct aggregation of different metrics as some metrics are plain sum or total of elements underneath whereas others are averages over weeks, averages over existing values and so forth. As you select an element from the context picker the system automatically determines appropriate rollup rule and applies it to your data.
An example of Week dimension. It has elements (years, months, weeks) with weeks being leaf-level elements, and months and years being rollups.