sheela

• Sep 7th, 2005

 

Function-based indexes can use any Function or Object method that is declared as repeatable. 
Queries using expressions can use the index. 
Ex:- CREATE INDEX sales_margin_inx 
ON sales(revenue - cost); 
 
 
Sql> SELECT ordid 
FROM sales 
WHERE (revenue - cost) > 1000; 
 
 
We have to enable Function-based indexes by enableing the following initialization parameters 
 
ALTER SESSION SET QUERY_REWRITE_ENABLED = TRUE; 
 
ALTER SESSION SET QUERY_REWRITE_INTEGRITY = TRUSTED;