Oracle Index Review

Oracle indexes refer to the data structure of ORACLE indexes in B tree structure and bitmap structure. The common indexes, reverse key indexes, and function indexes we usually use are tree structures and tree structures;

The bitmap structure only has leaf nodes. B-tree INDEX operations have unique scans, range scans, and FAST FULL INDEX scans (INDEX FAST FULL SCAN ),
Full index scan (index full scan); the access method of Bitmap indexes is only full index scan. All leaf nodes of Tree B have a bidirectional chain, which is sorted by the size of the index key value. As long as the result data is scanned, it must be on the leaf node, this is different from the B + tree (it may be a non-leaf node ). The reverse key, that is, the reverse key value, is used to solve the index hot block conflict.