Techniques are provided for improving efficiency of database systems, and in particular, to refreshing materialized views maintained by database systems and rewriting queries to access the materialized views. According to the approaches, a ranked materialized view is incrementally refreshed, and during...http://www.google.com/patents/US7912834?utm_source=gb-gplus-sharePatent US7912834 - Rewrite of queries containing rank or rownumber or Min/Max aggregate functions using a materialized view
