On your Oracle 12c database, you Issue the following commands to create indexes
SQL > CREATE INDEX oe.ord_customer_ix1 ON oe.orders (customers_id, sales_rep_id) INVISIBLE;
SQL> CREATE BITMAP INDEX oe.ord_customer_ix2 ON oe.orders (customers_id, sales_rep_id);
Which two statements are correct?
A.
Both the indexes are created; however, only the ORD_COSTOMER index is visible.
B.
The optimizer evaluates index access from both the Indexes before deciding on which index to use for
query execution plan.
C.
Only the ORD_CUSTOMER_IX1 index is created.
D.
Only the ORD_CUSTOMER_IX2 index is created.
E.
Both the indexes are updated when a new row is inserted, updated, or deleted In the orders table.
Explanation:
11G has a new feature called Invisible Indexes. An invisible index is invisible to the optimizer as default. Using
this feature we can test a new index without effecting the execution plans of the existing sql statements or we
can test the effect of dropping an index without dropping it.