11. Indexes can usually be created for both primary and secondary keys.

A. True
B. False

12. Each index consumes extra storage space and also requires overhead maintenance time whenever indexed data change value.

A. True
B. False

13. The HAVING clause acts like a WHERE clause, but it identifies groups that meet a criterion, rather than rows.

A. True
B. False

14. SQL is a data sublanguage.

A. True
B. False

15. The qualifier DISTINCT must be used in an SQL statement when we want to eliminate duplicate rows.

A. True
B. False