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Introduction to Bitmap Indexes
Each ROWID is mapped to a bitmap
Bitmap contains a bit for each distinct value in the column
- A 1 meaning that value is present for that row
- A 0 means that row does not have that value
Notes:
Bitmap indexes are index structures that store pointers to many rows with a single index key entry. Remember with a B-Tree index and index key entry points to a single row.