A method and apparatus provide bitmapped indexing with high granularity locking. Whenever a change is made to a data table upon which a bitmapped index is based, two differential entries are generated and stored as index entries in the bitmapped index. Each differential entry identifies a bit to be flipped...http://www.google.com.au/patents/US5899988?utm_source=gb-gplus-sharePatent US5899988 - Bitmapped indexing with high granularity locking
