Often, we have to present two data sources and compare them as if they were one. A typical example of this type of situation is the comparison of budget data to actuals. More often than not, the budgets are prepared at a much higher-level of grain than of actual data.
Consider the sales data that has been used in this chapter. We may define the grain of this as
Product. The actual grain of the table is, of course, a lower-level since it includes additional fields such as
Sales Order and
Geography, but for our purposes, this is the grain that we have chosen to present to the model user. Now, consider some high-level budget data that simply shows the budgeted sales (
USD Gross Sales) by