... The database divides your composite index into two logical subindexes, one with the key M and the other with the key F. Even though you haven't specified the leading column gender, the database ... normal B-tree index, the database inserts index values sequentially. If the next two primary key value generated by an Oracle sequence are 12345 and 12346, for example, the database stores both ... the database doesn't perform a range scan when you use a reverse key index, it can perform a fast full scan of the index. There could be a slight overhead in terms of CPU usage when the database...