8449255
Descripción
Test por Miguel Lucero, actualizado hace más de 1 año
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Creado por Miguel Lucero
hace más de 7 años
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Pregunta 1
Pregunta
1. One of the main functions of a database system is to provide timely answers to end users.
Respuesta
- True
- False
Pregunta 2
Pregunta
2. Good database performance is easy to evaluate
Respuesta
- True
- False
Pregunta 3
Pregunta
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.
Respuesta
- True
- False
Pregunta 4
Pregunta
4. Good database performance starts with good database design.
Respuesta
- True
- False
Pregunta 5
Pregunta
5. DBMS implementations are typically similar in complexity to two-tier client/server configurations.
Respuesta
- True
- False
Pregunta 6
Pregunta
6. A data file can contain rows from a single table alone.
Respuesta
- True
- False
Pregunta 7
Pregunta
7. The data cache caches system catalog data and the contents of the indexes.
Respuesta
- True
- False
Pregunta 8
Pregunta
8. The SQL cache stores the end-user written SQL.
Respuesta
- True
- False
Pregunta 9
Pregunta
9. To work with data, the DBMS must retrieve the data from permanent storage and place it in RAM.
Respuesta
- True
- False
Pregunta 10
Pregunta
10. The purpose of an I/O operation is to move data to and from different computer components or devices.
Respuesta
- True
- False
Pregunta 11
Pregunta
11. Working with data in the data cache is many times faster than working with data in the data files.
Respuesta
- True
- False
Pregunta 12
Pregunta
12. Fully equivalent means that the optimized query results are always the same as the original query.
Respuesta
- True
- False
Pregunta 13
Pregunta
13. The SQL execution activities are performed by the query optimizer.
Respuesta
- True
- False
Pregunta 14
Pregunta
14. All transaction management commands are processed during the parsing and execution phases of query processing.
Respuesta
- True
- False
Pregunta 15
Pregunta
15. An index scan is less efficient than a full table scan.
Respuesta
- True
- False
Pregunta 16
Pregunta
16. Indexes do not facilitate join operations.
Respuesta
- True
- False
Pregunta 17
Pregunta
17. Using index characteristics, a database designer can determine the best type of index to use.
Respuesta
- True
- False
Pregunta 18
Pregunta
18. A cost-based optimizer uses a set of preset rules and points to determine the best approach to execute a query.
Respuesta
- True
- False
Pregunta 19
Pregunta
19. The primary factor in determining the most efficient access plan is the I/O cost.
Respuesta
- True
- False
Pregunta 20
Pregunta
20. Most current-generation relational DBMSs perform automatic query optimization at the client end.
Respuesta
- True
- False
Pregunta 21
Pregunta
21. Indexes are very useful in small tables or tables with low sparsity.
Respuesta
- True
- False
Pregunta 22
Pregunta
22. Character field comparisons are faster than numeric, date, and NULL comparisons
Respuesta
- True
- False
Pregunta 23
Pregunta
23. In-memory database systems are optimized to store small portions of the database in disk storage alone
Respuesta
- True
- False
Pregunta 24
Pregunta
24. DBMS performance tuning includes global tasks such as managing the DBMS processes in primary memory and managing the structures in physical storage.
Respuesta
- True
- False
Pregunta 25
Pregunta
25. Maximizing disk contention is one of the general recommendations for the physical storage of databases.
Respuesta
- True
- False
Pregunta 26
Pregunta
26. RAID systems use a single disk to create storage volumes.
Respuesta
- True
- False
Pregunta 27
Pregunta
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.
Respuesta
-
a. client SQL
-
b. database SQL
-
c. SQL performance
-
d. DBMS performance
Pregunta 28
Pregunta
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.
Respuesta
-
a. client and server
-
b. database SQL
-
c. SQL performance
-
d. DBMS performance
Pregunta 29
Pregunta
29. When moving data from permanent storage to RAM, an I/O disk operation retrieves:
Respuesta
-
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.
Pregunta 30
Pregunta
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 .
Respuesta
-
a. procedure cache
-
b. buffer cache
-
c. supplements
-
d. extends
Pregunta 31
Pregunta
31. A(n) is a logical grouping of several data files that store data with similar characteristics.
Respuesta
-
a. procedure cache
-
b. table space
-
c. data cache
-
d. listener
Pregunta 32
Pregunta
32. A system table space, a user data table space, an index table space, and a temporary table space are examples of _____.
Respuesta
-
a. procedure caches
-
b. file groups
-
c. data caches
-
d. operation modes
Pregunta 33
Pregunta
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.
Respuesta
-
a. after; before
-
b. after; after
-
c. before; before
-
d. before; after
Pregunta 34
Pregunta
34. To work with data, a DBMS must retrieve the data from and place them in .
Respuesta
-
a. data files; procedure cache
-
b. RAM; data cache
-
c. permanent storage; RAM
-
d. temporary files; procedure cache
Pregunta 35
Pregunta
35. The data cache or is a shared, reserved memory area that stores the most recently accessed data blocks in RAM.
Respuesta
-
a. buffer cache
-
b. procedure cache
-
c. SQL cache
-
d. permanent storage
Pregunta 36
Pregunta
36. The is a shared, reserved memory area that stores the most recently executed SQL statements or PL/SQL procedures, including triggers and functions.
Respuesta
-
a. buffer cache
-
b. procedure cache
-
c. data cache
-
d. permanent storage
Pregunta 37
Pregunta
37. The process analyzes SQL queries and finds the most efficient way to access data.
Respuesta
-
a. optimizer
-
b. scheduler
-
c. listener
-
d. user
Pregunta 38
Pregunta
38. To generate database object statistics manually, following syntax should be used in Oracle: .
Respuesta
-
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;
Pregunta 39
Pregunta
39. Automatic query optimization means that the:
Respuesta
-
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.
Pregunta 40
Pregunta
40. The DBMS the SQL query and chooses the most efficient access/execution plan.
Respuesta
-
a. parses
-
b. executes
-
c. fetches
-
d. processes
Pregunta 41
Pregunta
41. Which of the following is the first step of query processing at the DBMS server end?
Respuesta
-
a. Executing
-
b. Parsing
-
c. Fetching
-
d. Delivering
Pregunta 42
Pregunta
42. The DBMS the data and sends the result set back to the client.
Respuesta
-
a. parses
-
b. executes
-
c. fetches
-
d. processes
Pregunta 43
Pregunta
43. If there is no index, the DBMS will perform a scan.
Respuesta
-
a. loop
-
b. range
-
c. row ID table access
-
d. full table
Pregunta 44
Pregunta
44. refers to the number of different values a column could possibly have.
Respuesta
-
a. Database statistics
-
b. Data sparsity
-
c. A bitmap index
-
d. Clustering
Pregunta 45
Pregunta
45. Bitmap indexes tend to use less space than a because they use bits instead of bytes to store their data.
Respuesta
-
a. hash index
-
b. sparse index
-
c. B-tree index
-
d. reverse index
Pregunta 46
Pregunta
46. Knowing the sparsity of a column helps you decide whether the use of is appropriate.
Respuesta
-
a. query processing
-
b. query optimization
-
c. an index
-
d. a full table scan
Pregunta 47
Pregunta
47. is the central activity during the parsing phase in query processing.
Respuesta
-
a. Clustering
-
b. Partitioning
-
c. Query validation
-
d. Query optimization
Pregunta 48
Pregunta
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.
Respuesta
-
a. ALL_ROWS
-
b. FIRST_ROWS
-
c. INDEX(P_QOH_NDX)
-
d. OPTIMIZATION_ROWS
Pregunta 49
Pregunta
49. In standard SQL, the optimizer hint FIRST_ROWS is generally used for mode processes.
Respuesta
-
a. batch
-
b. interactive
-
c. transaction
-
d. real-time
Pregunta 50
Pregunta
50. In standard SQL, the optimizer hint ALL_ROWS is generally used for mode processes.
Respuesta
-
a. interactive
-
b. real-time
-
c. batch
-
d. transaction
Pregunta 51
Pregunta
51. The LIKE conditional operator is used by the OPERAND1.
Respuesta
-
a. P_PRICE
-
b. V_STATE
-
c. P_QOH
-
d. V_CONTACT
Pregunta 52
Pregunta
52. The must be set large enough to permit as many data requests to be serviced from cache as possible.
Respuesta
-
a. data cache
-
b. SQL cache
-
c. sort cache
-
d. optimizer mode
Pregunta 53
Pregunta
53. The majority of primary memory resources will be allocated to the cache.
Respuesta
-
a. data
-
b. SQL
-
c. sort
-
d. optimizer
Pregunta 54
Pregunta
54. The cache is used as a temporary storage area for ORDER BY or GROUP BY operations, as well as for index-creation functions.
Respuesta
-
a. data
-
b. SQL
-
c. sort
-
d. optimizer
Pregunta 55
Pregunta
55. From the performance point of view, databases eliminate disk access bottlenecks.
Respuesta
-
a. RAID
-
b. distributed
-
c. index-organized
-
d. in-memory
Pregunta 56
Pregunta
56. The table space is used for transaction-recovery purposes.
Respuesta
-
a. system
-
b. user data
-
c. temporary
-
d. rollback segment
Pregunta 57
Pregunta
57. In the context of RAID levels, refers to writing the same data blocks to separate drives.
Respuesta
-
a. striping
-
b. mirroring
-
c. partitioning
-
d. aggregating
Pregunta 58
Pregunta
58. The table space is used to store the data dictionary tables.
Respuesta
-
a. system
-
b. user data
-
c. temporary
-
d. rollback segment
Pregunta 59
Pregunta
59. In the context of RAID levels, striped arrays provide:
Respuesta
-
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.
Pregunta 60
Pregunta
60. In RAID level 5,:
Respuesta
-
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.
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