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Former Member
May 31, 2012 at 06:01 AM

HANA Join Cardinality - Impact?



I was wondering what the impact on the cardinality settings on Attribute and Analytical views are. I am aware of the theory behind cardinalities 1:1, :n, n:1 and n:m. I can imagine what the impact of a "Join Type" (eg Inner, Left Outer etc) would be as the SQL script behind the scenes will use this join type to join the views. However, what is the role of the cardinality? For. e..g, if I get my cardinality wrong but my Join right, would a reporting query on an attr/analytical view bring back wrong results? or will there be just a performance impact? Does the SQL optimizer or the OLAP/Join engine optimize the SQL query generated based on the cardinality rule?

Any thoughts on this would be highly appreciated.

Thanks in Advance,