INDEXES

Indexing a table is an ‘access strategy’, that is, a way to sort and search records in the table. Indexes are essential to improve the speed with which the record/s can be located and retrieved from the table.
· An index is a schema object
· Is used by oracle server to speed up the retrieval of rows by using a pointer
· Is independent of the table it indexes
· Is used and maintained automatically by the oracle server.

ADDRESS FIELD IN THE INDEX
The address field of an index is called ROWID. ROWID is an internal generated and maintained, binary value, which identifies a record. The information in the ROWID columns provides Oracle engine the location of the table and a specific record in the Oracle database.
The ROWID format used by the Oracle is as follows:
BBBBBBB.RRRR.FFFF

SYNTAX: -
CREATE INDEX index_name ON tablename(columnname);

EXAMPLE: -
SQL> CREATE INDEX client_name ON banking1 (name);
Index created.