Star Transformation Process
The STAR transformation works by generating new sub-queries that can be used to drive a bitmap index access path for the fact table.
Let us assume that we have a table called fact, with bitmapped indexes on the columns state and region.
The STAR transformation is faster than a STAR join only if there are very few rows satisfying the simultaneous subqueries. If there are many rows returned from the sub-queries, then the STAR query execution plan is faster.
The next lesson examines function-based indexing techniques.