CREATE [UNIQUE] INDEX index_name
  ON table_name (column1, column2, . column_n)
  [ COMPUTE STATISTICS ];
 
 
-- UNIQUE indicates that the combination of values in the 
-- indexed columns must be unique.
 
-- COMPUTE STATISTICS tells Oracle to collect statistics during 
-- the creation of the index. The statistics are then used by the 
-- optimizer to choose an execution plan when SQL statements 
-- are executed.
 
-- for example: 
 
    CREATE INDEX supplier_idx
       ON supplier (supplier_name);
 
-- this example creates an index on the supplier table 
-- called supplier_idx.