Re: Bit-Mapped Indexing Routines---Beta Testers Wanted

Posted in 1996

Diana Rae — Fri, 06 Dec 1996 11:02:10 -0800 — source: Informix-list mailing list archive (1991-1998)

Bitmap indexes are used for high-performance query execution, such as in a data warehouse environment. They are best used on columns with a low cardinality. For example, if your data values for column "direction" were "up", "down", "left", and "right", the bitmap index would look as follows: direction = "up" 0 1 0 0 0 0 0 0 1 0 1 0 direction = "down" 0 0 1 1 0 0 1 1 0 0 0 1 direction = "left" 1 0 0 0 0 1 0 0 0 0 0 0 direction = "right" 0 0 0 0 1 0 0 0 0 1 0 0 rather than mapping the full value. ZOD wrote: > > I thought it was "bitWISE" indexing not "bitmapped" indexing. Please > correct me on this. > > Bill Gfroehrer...