Oracle Database Discussions

I know that function-based index can (kind-of) create index for only a portion of all the rows in a table,

create index idx_abc_01 on t_abc (case when end_dt > '01-APR-2008' then end_dt else null end);

/* to use the index, you have to use the same express in the filter clause */
select * from t_abc where xyz in ('O', 'S', 'X') and 
	case when end_dt > '01-APR-2008' then end_dt else null end 
		between '12-JUL-2008' and '15-JUL-2008';

But this approach is very inflexible because the expression in the where clause has to exactly match the index creation, otherwise that filtered index will not be used.

MS SQL Server 2008 has a new feature called - Filtered Indexes

CREATE NONCLUSTERED INDEX fidx_abc_01
    ON t_abc ( EndDate )
WHERE EndDate > '20040401';

select * from t_abc where EndDate between '20050121' and '20050130';

[url http://msdn.microsoft.com/en-us/library/cc280372.aspx]Filtered Indexes can be very helpful in both OLTP and DW. I'm wondering how to get the same thing done in Oracle.

Any suggestion beyond [url http://erturkdiriksoy.wordpress.com/2008/06/30/filtered-indexes-on-oracle/]Dunyada?