Virtual Catalogs in 10g database

Question

I have heard that you need an 11g catalog to use virtual catalogs. I have also heard that it's possible to run an 11g catalog from a 10g database. Is there a way to create the 11g catalog on a 10g database directly, or do I need to make it in an 11g database then datapump it to the 10g database?

Answer 1

Hej Henrik,
You can mimick it by creating a function based index (FBI), and optionally creating a view on top the table, ensuring that the FBI is used.
Example:
SQL> create table t (x number primary key check (x > 0), y number not null check (y > 0))
Table created.
SQL> create index fbi on t(x/y)
Index created.The index will now have a "virtual column" of x/y.
And if you like, put a view on top:
SQL> create view v
as
   select x, y, x/y as virtual_column
     from t
View created.
SQL> select * from v
where virtual_column = 3
no rows selected.Hilsen
Peter
Edited by: Peter on Mar 11, 2009 5:05 AM
- Added example