Database Reference
In-Depth Information
CalendarYear
CalendarQuarter
Month
Date
6
24
72
2191
The table has been calculated using the following query:
SELECT COUNT(DISTINCT CalendarYear) AS
CalendarYear,
COUNT(DISTINCT CalendarQuarter*CalendarYear)
AS CalendarQuarter,
COUNT(DISTINCT
MonthNumberOfYear*CalendarYear) AS [Month],
COUNT(DISTINCT DateKey) AS [Date]
FROM [AdventureWorksDW2012].[dbo].[DimDate]
The reason for multiplying CalendarQuarter and MonthNumberOfYear by the
CalendarYear attribute is that in the Date dimension these attributes have com-
posite keys that use both these attributes as keys. If you create an aggregation on
the month level, then you only need to summarize 72 cells to get the values for the
six years instead of summarizing the data on the date level, which would mean that
you would need to read 2191 cells. The month level aggregation could be used also
for the quarter level.
If you, on the other hand, would create an aggregation on the quarter level then that
aggregation could be used for the quarter and year level but not for the month level.
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