DATABASE CH 11

1. One of the main functions of a database system is to provide timely answers to end users. a. True b. False ANSWER

True

10. The purpose of an I/O operation is to move data to and from different computer components or devices. a. True b. False ANSWER

True

11. Working with data in the data cache is many times faster than working with data in the data files. a. True b. False ANSWER

True

12. Fully equivalent means that the optimized query results are always the same as the original query. a. True b. False ANSWER

True

14. All transaction management commands are processed during the parsing and execution phases of query processing. a. True b. False ANSWER

True

17. Using index characteristics, a database designer can determine the best type of index to use. a. True b. False ANSWER

True

18. The primary factor in determining the most efficient access plan is the I/O cost. a. True b. False ANSWER

True

26. DBMS performance tuning includes global tasks such as managing the DBMS processes in primary memory and managing the structures in physical storage. a. True b. False ANSWER

True

3. All factors must be checked to ensure that each system component operates at its optimum level and has sufficient resources to minimize the occurrence of bottlenecks. a. True b. False ANSWER

True

4. Good database performance starts with good database design. a. True b. False ANSWER

True

7. The data cache caches system catalog data and the contents of the indexes. a. True b. False ANSWER

True

9. To work with data, the DBMS must retrieve the data from permanent storage and place it in RAM. a. True b. False ANSWER

True

29. When moving data from permanent storage to RAM, an I/O disk operation retrieves a. an entire table. b. an entire physical disk block. c. only the row containing the attribute requested. d. only the attribute which was requested. ANSWER

b

31. A(n) is a logical grouping of several data files that store data with similar characteristics. a. procedure cache b. table space c. data cache d. listener ANSWER

b

32. A system table space, a user data table space, an index table space, and a temporary table space are examples of _____. a. procedure caches b. file groups c. data caches d. operation modes ANSWER

b

36. The is a shared, reserved memory area that stores the most recently executed SQL statements or PL/SQL procedures, including triggers and functions. a. buffer cache b. procedure cache c. data cache d. permanent storage ANSWER

b

39. Automatic query optimization means that the a. optimization takes place at compilation time by the programmer. b. DBMS finds the most cost-effective access path without user intervention. c. optimization process is scheduled and selected by the end user or programmer. d. database access strategy is defined when the program is executed. ANSWER

b

44. refers to the number of different values a column could possibly have. a. Database statistics b. Data sparsity c. A bitmap index d. Clustering ANSWER

b

49. In standard SQL, the optimizer hint FIRST_ROWS is generally used for mode processes. a. batch b. interactive c. transaction d. real-time ANSWER

b

54. The cache stores the most recently executed SQL statements. a. data b. procedure c. sort d. optimizer ANSWER

b

58. In the context of RAID levels, refers to writing the same data blocks to separate drives. a. striping b. mirroring c. partitioning d. aggregating ANSWER

b

a. Executing b. Parsing c. Fetching d. Delivering ANSWER

b

27. On the client side, the objective is to generate an SQL query that returns a correct answer in the least amount of time, using a minimum amount of resources at the server end. The activities required to achieve this goal are commonly referred to as tuning. a. client SQL b. database SQL c. SQL performance d. DBMS performance ANSWER

c

34. To work with data, a DBMS must retrieve the data from and place them in . a. data files; procedure cache b. RAM; data cache c. permanent storage; RAM d. temporary files; procedure cache ANSWER

c

37. To generate database object statistics manually, following syntax should be used in Oracle . a. ANALYZE <TABLE/INDEX> object_name; b. CREATE <TABLE/INDEX> object_name; c. ANALYZE <TABLE/INDEX> object_name COMPUTE STATISTICS; d. CREATE <TABLE/INDEX> object_name COMPUTE STATISTICS; ANSWER

c

42. The DBMS the data and sends the result set back to the client. a. parses b. executes c. fetches d. processes ANSWER

c

45. Bitmap indexes tend to use less space than a because they use bits instead of bytes to store their data. a. hash index b. sparse index c. B-tree index d. reverse index ANSWER

c

46. Knowing the sparsity of a column helps you decide whether the use of is appropriate. a. query processing b. query optimization c. an index d. a full table scan ANSWER

c

50. In standard SQL, the optimizer hint ALL_ROWS is generally used for mode processes. a. interactive b. real-time c. batch d. transaction ANSWER

c

55. The cache is used as a temporary storage area for ORDER BY or GROUP BY operations, as well as for index-creation functions. a. data b. SQL c. sort d. optimizer ANSWER

c

60. In the context of RAID levels, striped arrays provide a. increased read performance and fault tolerance. b. increased fault tolerance but decreased performance. c. increased read performance but no fault tolerance. d. neither fault tolerance nor good performance. ANSWER

c

28. On the server side, the database environment must be properly configured to respond to clients' requests in the fastest way possible, while making optimum use of existing resources. The activities required to achieve this goal are commonly referred to as tuning. a. client and server b. database SQL c. SQL performance d. DBMS performance ANSWER

d

30. A DBA determines the initial size of the data files that make up the database; however, as required, the data files can automatically expand in predefined increments known as . a. procedure cache b. buffer cache c. supplements d. extends ANSWER

d

43. If there is no index, the DBMS will perform a scan. a. loop b. range c. row ID table access d. full table ANSWER

d

47. is the central activity during the parsing phase in query processing. a. Clustering b. Partitioning c. Query validation d. Query optimization ANSWER

d

51. The LIKE conditional operator is used by the OPERAND1. a. P_PRICE b. V_STATE c. P_QOH d. V_CONTACT ANSWER

d

56. From the performance point of view, databases eliminate disk access bottlenecks. a. RAID b. distributed c. index-organized d. in-memory ANSWER

d

57. The table space is used for transaction-recovery purposes. a. system b. user data c. temporary d. rollback segment ANSWER

d

13. The SQL execution activities are performed by the query optimizer. a. True b. False ANSWER

False

15. An index scan is less efficient than a full table scan. a. True b. False ANSWER

False

16. Indexes do not facilitate join operations. a. True b. False ANSWER

False

19. A cost-based optimizer uses a set of preset rules and points to determine the best approach to execute a query. a. True b. False ANSWER

False

2. Good database performance is easy to evaluate. a. True b. False ANSWER

False

20. Most current-generation relational DBMSs perform automatic query optimization at the client end. a. True b. False ANSWER

False

21. Indexes are very useful in small tables or tables with low sparsity. a. True b. False ANSWER

False

22. Character field comparisons are faster than numeric, date, and NULL comparisons. a. True b. False ANSWER

False

23. Maximizing disk contention is one of the general recommendations for the physical storage of databases. a. True b. False ANSWER

False

24. RAID systems use a single disk to create storage volumes. a. True b. False ANSWER

False

25. In-memory database systems are optimized to store small portions of the database in disk storage alone. a. True b. False ANSWER

False

5. DBMS implementations are typically similar in complexity to two-tier client/server configurations. a. True b. False ANSWER

False

6. A data file can contain rows from a single table alone. a. True b. False ANSWER

False

8. The SQL cache stores the end-user written SQL. a. True b. False ANSWER

False

33. The data cache is where the data read from the database data files are stored the data have been read or the data are written to the database data files. a. after; before b. after; after c. before; before d. before; after ANSWER

a

35. The data cache or is a shared, reserved memory area that stores the most recently accessed data blocks in RAM. a. buffer cache b. procedure cache c. SQL cache d. permanent storage ANSWER

a

38. The process analyzes SQL queries and finds the most efficient way to access data. a. optimizer b. scheduler c. listener d. user ANSWER

a

40. The DBMS the SQL query and chooses the most efficient access/execution plan. a. parses b. executes c. fetches d. processes ANSWER

a

48. When setting optimizer hints, instructs the optimizer to minimize the overall execution time, that is, to minimize the time it takes to return the total number of rows in the query result set. This hint is generally used for batch mode processes. a. ALL_ROWS b. FIRST_ROWS c. INDEX(P_QOH_NDX) d. OPTIMIZATION_ROWS ANSWER

a

52. The must be set large enough to permit as many data requests to be serviced from cache as possible. a. data cache b. SQL cache c. sort cache d. optimizer mode ANSWER

a

53. The majority of primary memory resources will be allocated to the cache. a. data b. SQL c. sort d. optimizer ANSWER

a

59. The table space is used to store the data dictionary tables. a. system b. user data c. temporary d. rollback segment ANSWER

a

61. In RAID level 5, a. the data and the parity data are striped across separate drives. b. the data blocks are spread over separate drives and are duplicated. c. the array requires a minimum of two drives and is known as a striped array. d. the array requires a minimum of five drives and is known as duplexing. ANSWER

a