Ravi Prakash Pichika

• Jun 11th, 2005

 

An Index is a tree structure that allows direct access to a row in a table. Indexes can be classified based on their logical design or on their physical implementation. 
 
The Logical classification groups indexes from an application perspective, while the physical classification is derived from the way the indexes are stored

soccer_champ

• Jun 18th, 2005

 

An index is a schema object that can speed up the retrieval of rows by using pointers. If you do not have an index, then a full table scan occurs. Its purpose is to reduce disk I/O by using an indexed path to locate data quickly. If a table is dropped, the corresponding indexes are also dropped. 
In case of doubt, contact me : bobby_1020@hotmail.com

srujana

• Aug 23rd, 2005

 

it is created in existing table to locate rows more quickly&efficiently. 
the users cannot see the indexes,they are just used to speed up the queries

Taj_N

• Jul 16th, 2007

 

An Index is based on tree structre that allow direct access to a row in a table, oracle uses different type of index
1) B-Tree Index
2) Bitmap Index