What are the type of indexes in oracle? How to identify the index need to create?
Oracle Database provides several indexing schemes that provide complementary performance functionality. These are:
- B-tree indexes: the default and the most common
- B-tree cluster indexes: defined specifically for cluster
- Hash cluster indexes: defined specifically for a hash cluster
- Global and local indexes: relate to partitioned tables and indexes
- Reverse key indexes: most useful for Oracle Real Application Clusters applications
- Bitmap indexes: compact; work best for columns with a small set of values
- Function-based indexes: contain the precomputed value of a function/expression Domain indexes: specific to an application or cartridge.
Source: http://docs.oracle.com/cd/B19306_01/server.102/b14231/indexes.htm