Creating bitmaps from multi-level identifiers

摘要

A method and apparatus for generating and using bitmaps in a database system that employs multi-level identifiers is provided. The generated bitmaps include bits that correspond to the identifiers that have been assigned to existing records, as well as bits that correspond to all intervening multi-level identifiers that have not yet been assigned. Therefore, when new rows are inserted into the table associated with the bitmap, new bits do not have to be inserted into the existing bitmap. When existing rows are deleted, the bits that correspond to the deleted rows are not themselves deleted, but are simply set to a value that indicates that the corresponding row does not satisfy the criteria associated with the bitmap.