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 statement 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.
Wrong answer!
the question would be
SQL > CREATE INDEX oe.ord_customer_ix1 ON oe.orders (customers_id, sales_rep_id)
SQL> CREATE BITMAP INDEX oe.ord_customer_ix2 ON oe.orders (customers_id, sales_rep_id)INVISIBLE;
In order to make Answer A correct
The question A should be
Both the indexes are created; however, only the ORD_COSTOMER_IX2 index is visible
So answers are AE