A.An INVISIBLE index is not maintained when Data Manipulation Language (DML) is performed on its underlying table.

B.An index can be created as part of a CREATE TABLE statement.

C.If a query filters on an indexed column then it will always be used during execution of the query

D.A UNIQUE and non-unique index can be created on the same table column

E.A descending index is a type of function-based index

F.A DROP INDEX statement always prevents updates to the table during the drop operation

A.An error

B.0 rows

C.1 ROW

D.2 rows

A.ORDER BY comm DESC NULLS LAST, ename

B.ORDER BY NVL(comm,0) ASC NULLS FIRST, ename

C.ORDER BY NVL(comm,0) ASC NULLS LAST, ename

D.ORDER BY NVL(enam,0) DESC, ename

A.It can merge rows only from tables.

B.It can combine rows from multiple tables conditionally to insert into a single table.

C.It can update the same row of the target table multiple times.

D.It can update, insert, or delete rows conditionally in multiple tables.

E.It can use views to produce source rows.

F.It can use subqueries to produce source rows.

A.Roles are assigned to users using the ALTER USER statement.

B.Privileges are assigned to a role using the GRANT statement.

C.A role is a named group of related privileges that can only be assigned to a user.

D.Roles are assigned to roles using the ALTER ROLE statement.

E.A single role can be assigned to multiple users.

F.A single user can be assigned multiple roles.

G.Privileges are assigned to a role using the ALTER ROLE statement.