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Should you use tabular or multi-dimensional SSAS mode? Here's the answer!
Part five of a seven-part series of blogs
If you're building a data warehouse, you'll want to know whether you should be creating cubes using the legacy multi-dimensional Analysis Services server mode, or creating data models in the new tabular mode. This blog gives Wise Owl's take on the subject.
Not only is the architecture different for the two approaches to using Analysis Services; so too is the underlying language.
Suppose that we want to show the total value of transactions in a pivot table (that is, we want to sum Price * Quantity):
This pivot table shows the total quantity sold, and also the total value of all transactions.
Here's a DAX formula which would give the total value measure:
A typical DAX expression, giving total price * quanttiy.
Suppose we want to calculate the transaction value as in the above example. Here's an MDX calculation which would create the necessary measure:
A measure in MDX to create the expression for summing.
As this shows, neither DAX or MDX look remotely like SQL, although DAX has a lot in common with the Excel formula language.
I don't claim to have built huge models containing terabytes of data, but reading through other blogs, it seems reasonable to state two truths:
However, I think the DAX versus MDX question is a red herring. You wouldn't choose Oracle over SQL Server because you preferred Oracle SQL to T-SQL, and you shouldn't choose an Analysis Services server model based on the language that you'll have to learn.
|Parts of this blog|
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