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Star Transform condition?

P: n/a
Can someone please clear up some confusion I am having on Star
Transformations: I have read about the conditions for Star
Transformations, especially this onen (from 9i Data Warehousing

"A prerequisite of the star transformation is that there be a
single-column bitmap index on every join column of the fact table.
These join columns include all foreign key columns"

Does this mean every join column in a particular query, or every Fact
record FK column in the table ?

I have a single col bitmap index on all but one of my FK columns in a
fact table; the column in question is the primary key and links to a
"Descriptive" Dimension - one record per Fact. Since this column is the
PK I have a PK constraint on it...and therefore cannot have a Bitmap
Index in addition. I have Star_Transformation option enabled, I'm
using the CBO but still not getting a Star Query Plan.

Reading the documentation, I would have thought that if this column is
not used in a query I would get a Star Query Plan, but when it was
used I would not.


Jul 19 '05 #1
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