Vicious1.com bitmap estlcam7/13/2023 ![]() ![]() Bitmap indexes use bit arrays (commonly called bitmaps) and answer queries by performing bitwise logical operations on these bitmaps. ![]() The extreme case of low cardinality is Boolean data (e.g., does a resident in a city have internet access?), which has two values, True and False. A bitmap index is a special kind of database index that uses bitmaps.īitmap indexes have traditionally been considered to work well for low- cardinality columns, which have a modest number of distinct values, either absolutely, or relative to the number of records that contain the data.
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