April 1, 2014 at 1:09 pm
I'm trying to read up on SSAS and going through some tutorials.
They show the DimDate and FactResellerSales.
What I don't understand is how Fact can have 3 date dimensions all to the same DimDate table.
Kimball (and what I though was common sense at least in my head) says you need a role playing dimension.
I assume I am missing something here?
April 1, 2014 at 2:40 pm
Those are the role playing dimensions.
You have the order date, the ship date and the due date.
This is realized by joining 3 times to the same date dimension, but each time using a different date column from the fact table.
OrderDateKey -- DateKey
ShipDateKey -- DateKey
DueDateKey -- DateKey
You could use 3 different views on top of the date dimension, but the result is the same.
When you create the cube, you add the date dimension three times as a cube dimension and there you can rename them as well.
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MCSE Business Intelligence - Microsoft Data Platform MVP
April 1, 2014 at 4:44 pm
OF COURSE, I forgot about the CUBE and it being an abstraction layer.
So when it generates itself it will just know that it joins to the Date dimension and the cube will populate up as needed.
Thanks!
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