042详解 51-100题

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51. You have a large amount of historical data in an operating system file. Some analysts in your organization need to query this data. The file is too large to load into your current database. Which is the most effective method to accomplish the task?

A) Upgrade the hardware/memory to accommodate the data.

B) Load the data into your database by using the PARALLEL clause.

C) Give analysts DBA privilege, so that they can query DBA_EXTERNAL_TABLES.

D) Use an external table so you can have the metadata available in your database, but leave the data in the operating system files.

答案：D

解析：外部表注意事项：

数据在数据库的外部组织，是操作系统文件。　
操作系统文件在数据库中的标志是通过一个逻辑目录来映射的。　　　　
数据是只读的。（外部表相当于一个只读的虚表）　
不可以在上面运行任何DML操作，不可以创建索引。　　
可以查询操作和连接，可以并行操作。

52. A user receives the following error while executing a query:

ORA-01555: snapshot too old

Which two options can be the solutions to avoid such errors in future? (Choose two.)

A) increase the size of redo log files

B) increase the size of the undo tablespace

C) increase the size of the Database Buffer Cache

D) increase the size of the default temporary tablespace

E) enable the retention guarantee for the undo tablespace

答案：BE

解析：If in Automatic Undo Management mode, increase undo_retention setting（E）. Otherwise, use larger rollback segments（B）

53. You executed the following command to export the EMPLOYEES table from a remote Machine:

$ EXPDP hr/hr@data.us.oracle.com

DUMPFILE=my_dir：exp_hr.log

LOGFILE=data_pump_dir：log_hr.log

TABLES=employees

What would be the outcome of this command?

A) The command would execute successfully and the export dump file would be created in the destination of the directory object MY_DIR.

B) The command would execute successfully. But log file would not be created as DATA_PUMP_DIR directory is only accessible to user with SYSDBA privilege.

C) The command fails with an error because DATA_PUMP_DIR directory have higher precedence over the per-file directory.

D) The command fails with an error because no absolute path is specified for log file and dumpfile.

答案：A

解析：DUMPFILE=[directory_object:]file_name [,….]

Directory_object用于指定目录对象名,file_name用于指定转储文件名.需要注意,如果不指定directory_object,导出工具会自动使用DIRECTORY选项指定的目录对象

LOGFILE=[directory_object:]file_name

Directory_object用于指定目录对象名称,file_name用于指定导出日志文件名.如果不指定directory_object.导出作用会自动使用DIRECTORY的相应选项值.

NETWORK_LINK

指定数据库链名,如果要将远程数据库对象导出到本地例程的转储文件中,必须设置该选项.

54. You execute the following command to audit the database activities:

SQL> AUDIT DROP ANY TABLE BY scott BY SESSION WHENEVER SUCCESSFUL;

What is the effect of this command?

A) One audit record is created for the whole session if user SCOTT successfully drops one or more tables in his session.

B) One audit record is created for every session when any user successfully drops a table owned by SCOTT.

C) One audit record is created for each successful DROP TABLE command executed by any user to drop tables

owned by SCOTT.

D) One audit record is generated for the session when SCOTT grants the DROP ANY TABLE privilege to other users in

his session.

E) One audit record is created for each successful DROP TABLE command executed in the session of SCOTT.

答案：A

解析：创建一个审计记录整个会话中scott用户成功删除表

55. Examine the following commands executed in your database:

SQL> ALTER SESSION RECYCLEBIN=ON;

Session altered

SQL> CREATE TABLE emp TABLESPACE tbsfd AS SELECT * FROM hr.employees;

Table created.

Further, you executed the following command to drop the table:

SQL> DROP TABLE emp;

Table dropped.

What happens in this scenario?

A) The table is moved to the SYSAUX tablespace.

B) The table is moved to the SYSTEM tablespace.

C) The table is removed from the database permanently.

D) The table is renamed and remains in the TBSFD tablespace.

答案：D

解析：打开回收站功能，当你drop一个表后，该表会被改名同时还放在原来的表空间里

56. Which two statements are true about a bitmap index? (Choose two.)

A) It is recommended for the columns that have unique values.

B) It can be converted to a B-tree index by using the ALTER INDEX command.

C) It has a bitmap segment for each distinct value in the key column, containing a string of bits in which each bit represents the presence or absence of a key column value.

D) Updating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.

答案：CD

解析：位图索引---在关键列上，每一个不同值都有位图段，更新关键列，会锁住位图段，包含主要要被更新的段

1：bitmap索引是分段存储的，也就是说很多条记录可能是分做了N段来存储，也就是有N个begin/end ,当新的记录 insert 而使用以前未曾使用过的物理地址的时候，会产生一个bitmap 段来存储，就算只有一条记录

2：当删除一条记录的时候,在bitmap 索引上做了一个delete 的标记并用一新的记录来标记了

3: 当 dml发生的时候，会lock住某个值的存储bit的那一rowid所在的记录，参考下面的 row 中 lock ,这样显然会影响并发

57. Your database is configured with the following parameters related to SGA)

SGA_TARGET=256MB

SHARED_POOL_SIZE=32MB

DB_CACHE_SIZE=100MB

LARGE_POOL_SIZE=0

JAVA_POOL_SIZE=0

STREAMS_POOL_SIZE=0

Which two statements are true about the configuration? (Choose two.)

A) The SGA_TARGET value cannot be sized smaller than 100 MB.

B) The shared pool and the default buffer pool will not be sized bigger than 32 MB and 100 MB, respectively.

C) The shared pool and the default buffer pool will not be sized smaller than 32 MB and 100 MB, respectively.

D) 124 MB (256 minus 132) of memory is available for use by all the manually sized components.

E) 124 MB (256 minus 132) of memory is available for use by all the manually and automatically sized components.

答案：CE

解析：在自动内存管理下shared pool如果指定了初始大小是不会减小的,即最低值不会低于设定的值

58. The application workload on your database is same between 10 a.m. and 11 a.m. on weekdays. Suddenly you observe poor performance between 10 a.m. and 11 a.m. in the middle of the week. How would you identify the changes in configuration settings, workload profile, and statistics to diagnose the possible causes of the

performance degradation?

A) by using the SQL access advisor

B) by using the Automatic Workload Repository report

C) by running the Automatic Database Diagnostic Monitor (ADDM)

D) by using the Automatic Workload Repository Compare Period report

E) by analyzing the output of the V$ACTIVE_SESSION_HISTORY view

答案：D

解析：题目要求的是从配置设置，工作量概要文件和状态来诊断可能的性能问题，所以选择D，AWR报告

AWR概述

1. 自动工作量资料档案库 (AWR)是 SYS 拥有的永久性系统性能统计信息的集合。

2. AWR 驻留在 SYSAUX表空间中。

3. 快照是在特定时间捕获并存储在 AWR中的一组性能统计信息。快照用于计算统计信息的更改率

4. 每个快照都用一个快照序列号 (snap_id)进行标识，该序列号在 AWR 中是唯一的。

5. 默认情况下，快照每 60分钟生成一次。通过更改快照INTERVAL 参数可以调整此频率。

59. The application development team has developed PL/SQL procedures and functions for different purposes and calls them as and when required. The loading of individual procedures or functions into memory degrades performance with every call. Also, it causes a security problem for individual subprograms and loss of program units when the whole system is transported into a new location.

Which method would you recommend to the application developers to solve this problem?

A) avoiding the use of cursors in the subprograms

B) using anonymous PL/SQL blocks instead of subprograms

C) referring to views instead of tables inside the subprograms

D) creating PL/SQL packages to include interrelated subprograms

答案：D

解析：注意是solve this problem

60. Which three pieces of information are to be mandatorily provided while creating a new listener using

Enterprise Manager Database Control? (Choose three.)

A) the port used by the listener

B) the protocol used by the listener

C) the server name where the listener runs

D) the log file and trace file destination for the listener

E) the database services to be registered with the listener

答案：ABC

解析：使用EM创建监听时必须提供端口，协议，监听对应的服务器名

61. What are the consequences of executing the SHUTDOWN ABORT command? (Choose two.)

A) The database files are synchronized.

B) Uncommitted changes are not rolled back.

C) The database is closed, but the instance is still started.

D) Database buffers and redo buffers are not written to the disk.

E) The database undergoes automatic media recovery during the next startup

答案：BD

解析：shutdown abort后--没有commited的数据不会rollback，Database buffers and redo buffers are not written to the disk.

关于E选项：

当数据库执行了SHUTDOWN ABORT或者由于操作系统、主机等原因宕机重启后，在ALTER DATABASE OPEN的时候，就会自动做实例恢复.

实例恢复: 启动的时候从某个点把日志文件里内容完全写到数据文件,打开,把没有提交的rollback

62. User SCOTT wants to export his objects using Oracle Data Pump and executes the following command:

$ expdp scott/tiger

directory = EXPORT_DIR

dumpfile = scott.dmp

include = table

include = view: "like '%DEPARTMENTS%'"

content = DATA_ONLY

Which task would the command accomplish?

A) Oracle Data Pump would export only the data of all of the tables and views.

B) Oracle Data Pump would export all of the table structures along with data and all the views.

C) Oracle Data Pump would export the table data and the view definitions where the view name contains a string named DEPARTMENTS.

D) Oracle Data Pump would export the table data and the view definitions with data where view name contains a string named DEPARTMENTS.

E) Oracle Data Pump would export all of the table structures and the view definitions with data where view name contains a string named DEPARTMENTS.

答案：C

解析：导出表中的数据以及包含DEPARTMENTS的视图定义

63. View the Exhibit, and examine the alert messages.

You added space to the TEST tablespace to bring the space usage below the threshold value.

Which statement is true about the Tablespace Full alert?

A) The alert is purged because it is a threshold alert.

B) The alert is cleared and transferred to the alert log file.

C) The alert is automatically cleared and sent to the alert history.

D) The alert appears in Oracle Enterprise Manager Database Control until it is manually cleared.

答案：C

解析：在EM上的表空间空间不够用的告警信息会在你扩大表空间后，自动被清除，同时移动到alter history

select * from dba_outstanding_alerts 警告记录地方,只记录根据度量产生的

select * from dba_alert_history (警告归档后的地方,记录所有的)

64. In your database, the Log Writer (LGWR) process is unable to write to a member of a current redo log

group due to read/write failure. Which two effects would you see in your database? (Choose two.)

A) The database instance aborts.

B) The database operation temporarily halts till the member becomes available.

C) Writing proceeds as normal. LGWR writes to the available members of a group and ignores the unavailable members.

D) The member would be marked as STALE and an error message would be written to the alert log file and LGWR trace file.

E) The status of the group changes to INACTIVE and an error message would be written to the alert log file and LGWR trace file.

65. You executed the following command to start the database:

SQL> STARTUP

ORACLE instance started.

Total System Global Area 281018368 bytes

Fixed Size 789000 bytes

Variable Size 229635576 bytes

Database Buffers 50331648 bytes

Redo Buffers 262144 bytes

ORA-00205: error in identifying controlfile, check alert log for more info

Which view would you query at this stage to investigate this missing control file?

A) V$INSTANCE

B) V$CONTROLFILE

C) DBA_CONTROL_FILES

D) V$DATABASE_PROPERTIES

E) V$CONTROLFILE_RECORD_SECTION

答案：B

解析：v$controlfile lists the names of the control files.You can confirm whether the control files have broken by v$controlfile.status.

66. Which statement is true about the loss of system-critical data files in ARCHIVELOG mode?

A) The data files can be recovered till the last committed transaction.

B) The data files can be recovered without shutting down the database.

C) The data file is taken offline automatically; the database remains open.

D) The data files can be recovered to the time of the most recent backup.

答案：A

解析：在归档模式下，只要归档文件存在，数据库可以恢复到任意时刻，最近可恢复到最后次commit

67. Which two statements about bigfile tablespaces are true? (Choose two.)

A) The bigfile tablespace have only one data file.

B) The segment space management is automatic.

C) The extent management is dictionary managed.

D) The database can have only one bigfile tablespace.

E) The bigfile tablespace can be converted to a smallfile tablespace.

答案：AB

解析： BIGFILE有且只有一个数据文件，BIGFILE的段空间是自动管理的

68. User A executes the following command to update the TRANS table)

SQL> UPDATE B.trans SET tr_amt=tr_amt+500 WHERE c_code='C005';

Before user A issues a COMMIT or ROLLBACK command, user B executes the following command on the

TRANS table:

SQl> ALTER TABLE trans MODIFY (tr_type VARCHAR2 (3));

What would happen in this scenario?

A) The transaction for user A is rolled back.

B) The ALTER TABLE command modifies the column successfully.

C) The ALTER TABLE command fails due to the resource being busy.

D) The ALTER TABLE command waits until user A ends the transaction.

答案：C

解析：SQL> alter table wdz2 modify (memo varchar(22));

alter table wdz2 modify (memo varchar(22))

第 1 行出现错误:

ORA-00054: 资源正忙,但指定以 NOWAIT 方式获取资源

69. You backed up the control file to trace. Which statement is true about the trace file generated?

A) The trace file is in binary format.

B) The trace file has a SQL script to re-create the control file.

C) The trace file is a backup set created during the backup of the control file.

D) The trace file contains the instructions to manually re-create the control file.

E) The trace file is an image copy of the control file created during the backup of the control file.

答案：B

解析：There are two different ways to backup controlfiles.

One is:

ALTER DATABASE BACKUP CONTROLFILE TO TRACE (as filename);

This statement is used to create a trace file include sql statement for creating controlfile

Another is :

ALTER DATABASE BACKUP CONTROLFILE TO filename;

This statement is used to create binary file.it’s a backup controlfile for current controlfile.

70. You created a response file and want to check it before starting installations in silent mode. You started installation of Oracle software in interactive mode by providing the response file. In the middle of the installation, you realize that the behavior of the Oracle Universal Installer (OUI) is not consistent with the response file.

What action would you take to detect the cause of this behavior?

A) Compare the contents of the install.log file with the response file.

B) Refer to the contents of the oraInst.loc file to verify the steps performed by OUI.

C) Compare the contents of the installActions.log file with that of the response file.

D) Refer to the alert log file for information regarding the actions performed by OUI during installation.

答案：C

解析：安装数据库时OUI的行为跟响应文件不一致，这时应该比较installActions.log和response file查看原因

71. View the Exhibit and analyze the CREATE TABLE statements used to create the ITEMS and ORDERS tables.

The ITEMS table has 50 rows and ORDERS table has 500 rows. Because you decide to not deal with the item

code 188 in future, you execute the following command to remove the item:

SQL> DELETE FROM items WHERE item_code=188;

What is the effect of this command?

A) The command fails with integrity violation error.

B) The row containing the value 188 corresponding to the ITEM_CODE column is deleted from the ITEMS table, and

the foreign key constraint is disabled in the ORDERS table.

C) The row containing the value 188 corresponding to the ITEM_CODE column is deleted from the ITEMS table, and

the dependent rows in the ORDERS table are also deleted automatically.

D) The row containing the value 188 corresponding to the ITEM_CODE column is deleted from the ITEMS table, and

the dependent rows in the ORDERS table are populated with NULL values in their ITEM_CODE columns.

答案：C

解析：因为添加了delete cascade索引删除主键的同时会自动删除对应外键

72. Your database is open and users are connected using the LISTENER listener. The new DBA of the system

stops the listener by using the following command:

LSNRCTL> STOP

What would happen to the sessions that are presently connected to the database instance?

A) The sessions are able to perform only queries.

B) The sessions are not affected and continue to function normally.

C) The active transactions are rolled back and the sessions get terminated.

D) The sessions are not allowed to perform any operations till the listener is started.

答案：B

解析：已连接的会话，当停止监听时不会中断

73. You have been recently hired as a database administrator. Your senior manager asks you to study the

production database server and submit a report on the settings done by the previous DBA. While observing

the server settings, you find that the following parameter has been set in the parameter file of the database:

REMOTE_OS_AUTHENT = TRUE

What could have been the reason to set this parameter as TRUE?

A) to enable operating system authentication for a remote client

B) to restrict the scope of administration to identical operating systems

C) to allow the start up and shut down of the database from a remote client

D) to enable the administration of the operating system from a remote client

E) to disable the administration of the operating system from a remote client

答案：A

解析：初始化参数REMOTE_OS_AUTHENT用来控制是否允许远端操作系统验证，默认情况下，数据库只运行本地服务器上的操作系统验证

74. You are working on a database created with the Oracle Database 10g software in which the initialization

parameter COMPATIBLE is set to 10.0.0. The hr_tbs tablespace in the database is created as follows:

CREATE TABLESPACE hr_tbs DATAFILE '/oracle/oradata/hr_tbs.dbf' SIZE 50M;

View the Exhibit to see the properties of the database.

Which statement is correct in this scenario?

A) hr_tbs is a bigfile tablespace.

B) hr_tbs is a dictionary-managed tablespace.

C) All the tablespaces in the database will be locally managed by default.

D) All the tablespaces in the database must be of the smallfile tablespace type.

E) The tablespace type bigfile or smallfile must be mentioned in the command.

答案：C

解析：SQL> select * from database_properties Where property_name='DEFAULT_TBS_TYPE';

PROPERTY_NAME PROPERTY_VALUE DESCRIPTION

-------------------- --------------- ------------------------

DEFAULT_TBS_TYPE SMALLFILE Default tablespace type

SQL>CREATE BIGFILE TABLESPACE bigtbs

DATAFILE ‘/u01/oradata/big_tbs_data_01.dbf’ SIZE 1024 M;

SQL> ALTER DATABASE SET DEFAULT bigfile TABLESPACE;

SQL> CREATE TABLESPACE bigtbs DATAFILE '/us01/oradata/bigtbs_02.dbf' size 1M;

SQL> select TABLESPACE_NAME, BIGFILE from DBA_TABLESPACES;

TABLESPACE_NAME BIGFILE

------------------------------ ---------

USERS SMALLFILE BIGTBS BIGFILE

并不一定需要在创建的时候指明类型,使用缺省指定的类型来创建,E错，也可以在创建的时候指定创建不同类型的表空间,D错

75. You perform differential incremental level 1 backups of your database on each working day and level 0

backup on Sundays. Which two statements are true about the differential incremental backups? (Choose two.)

A) The backup performed on Sundays contains all the blocks that have ever been use in the database.

B) The backup performed on Sundays contains all the blocks that have changed since the last level 1 backup.

C) The backup performed on each working day contains all the blocks that have changed since the last level 0 or level 1 backup.

D) The backup performed on each working day contains all the blocks that have changed since the last level 0 backup.

答案：AC

解析：备份分为完全备份和增量备份

完全备份：创建所备份的文件中包含数据的所有数据块的副本

增量备份：创建一个包含自以前某次备份以来更改过的所有数据块的副本（分为级别0和级别1两种）

级别0：等同于完全备份

级别1:

累积备份：备份自上次级别 0 备份以来的所有更改

差异备份：备份自上次增量备份以来的所有更改（可以采用级别 0 或级别1）

76. Users of HR schema complain about slower-than-normal performance. On investigation the DBA found that maintenance was recently performed on some of the tables. The DBA traced the query that takes longer than normal to execute.

View the Exhibit exhibit_before.

After the DBA resolves the problem, the query performs normally.

View the Exhibit exhibit_after.

What action would the DBA have taken to resolve the performance problem?

A) analyzed the EMPLOYEES table to collect the current statistics

B) moved the EMPLOYEES table in to a locally managed tablespace

C) moved the EMPLOYEES table to another location in the same tablespace

D) reorganized the associated indexes for the EMPLOYEES table that were in an unusable state

E) moved the indexes associated with the EMPLOYEES table to the same tablespace where the EMPLOYEES table

Exists

答案：D

解析：从第一张图看到同样的查询走了一个全表扫描。所以我们有理由相信，索引无效了导致执行计划有问题了。
第二张图应该就是dba重建了该索引后，同样的sql走了索引。
an unusable state表示索引的状态。在user_indexes的status字段中体现。

77. Your database is having two control files, three redo log file groups with two members in each group.

Failure of which file would cause an instance to shut down?

A) any control file

B) any archive log file

C) one of the redo log members

D) loss of the initialization parameter file

E) any data file belonging to the default permanent tablespace

答案:A

解析：所有的控制文件正常才可以打开数据库

78. Which two operations can be flashed back using the Flashback technology? (Choose two.)

A) DROP USER SMITH;

B) DROP TABLE EMPLOYEES;

C) DROP TABLESPACE USERS;

D) ALTER TABLE SALES_REP DROP PARTITION P1;

E) ALTER TABLE EMPLOYEES DROP COLUMN DESIG_ID;

答案：B

解析：在FLASHBACK DATABASE的时候,是可以恢复删除的非系统用户的 B是flash drop table

79. Which two statements regarding the LOGGING clause of the CREATE TABLESPACE...statement are correct? (Choose two.)

A) This clause is not valid for a temporary or undo tablespace.

B) If the tablespace is in the NOLOGGING mode, no operation on the tablespace will generate redo.

C) The tablespace will be in the NOLOGGING mode by default, if not specified while creating a tablespace.

D) The tablespace-level logging attribute can be overridden by logging specifications at the table, index, materialized view, materialized view log, and partition levels.

答案：AD

解析：

logging clause

这个子句声明这个表空间上所有的用户对象的日志属性（缺省是logging），包括表，索引，分区，物化视图，物化视图上的索引，分区。

FORCE LOGGING

使用这个子句指出表空间进入强制日志模式。此时，系统将记录表空间上对象的所有改变，除了临时段的改变。这个参数高于对象的nologging选项。

注意：设置这个参数在临时表空间和回滚表空间中不能使用这个选项。

D选项是说在表空间级别的logging选项没有在表、视图等的级别高

80. Which two statements are true about the Automatic Database Diagnostic Monitor (ADDM)? (Choose two.)

A) The ADDM runs after each AWR snapshot is collected.

B) The ADDM requires at least four AWR snapshots for analysis.

C) The ADDM analysis provides only the diagnostic information but does not provide recommendations.

D) The results of the ADDM analysis are stored in the Automatic Workload Repository (AWR).

E) The ADDM calls other advisors if required, but does not provide recommendations about the advisors.

答案：AD

解析：Automatic Database Diagnostic Monitor (ADDM) ADDM 在创建每个AWR 快照之后自动运行。每次创建快照后，ADDM 都会分析与最后两个快照对应的时段。多数情况下，ADDM 会为检测到的问题提供建议解决方案，甚至可以量化这些建议案的优势。ADDM分析的结果存放在AWR中。

81. You want to refer the employee personal information stored in operating system(OS) files in EMPLOYEE

table. You plan to add a new column to EMPLOYEE table to achieve this.

Which data type would you use for the new column?

A) BLOB

B) CLOB

C) BFILE

D) LONG RAW

答案：C

解析：

BFILE 二进制文件,存储在数据库外的操作系统文件，只读的。把此文件当二进制处理。

BLOB 二进制大对象。存储在数据库里的大对象，一般是图像声音等文件。

CLOB 字符型大对象。一般存储大数量文本信息。存储单字节，固定宽度的数据。 NCLOB 字节字符大对象。存储单字节大块，多字节固定宽度，多字节变宽度数据。

82. You want to monitor and control the resource usage by sessions. You want to be warned automatically

when more than 100 sessions are opened with your database. What action would you take to achieve this?

A) Use the Database Resource Manager.

B) Set the limits in the profiles used by users.

C) Modify the SESSIONS initialization parameter.

D) Set the warning threshold for the Current Logons Count metric.

答案：D

解析：license_max_users 限制被授权使用oracle的人数到这个数后不能建用户
license_max_sessions达到会话连接的最大数，到了后只有拥有restricted session 权限用户能连接
license_max_warning 就是警告
查v$license ~~~~~可以设为0 就是无限

83. In your database, the STATISTICS_LEVEL initialization parameter is set to BASIC. What is the impact of

this setting?

A) The optimizer statistics are collected automatically.

B) Only the timed operating system (OS) statistics and plan execution statistics are collected.

C) The Oracle server dynamically generates the necessary statistics on tables as part of query optimization.

D) The snapshots for the Automatic Workload Repository (AWR) are not generated automatically.

E) Snapshots cannot be collected manually by using DBMS_WORKLOAD_REPOSITORY PACKAGE.

答案：D

解析：STATISTICS_LEVEL 参数控制数据库中所有主要统计信息的收集或指导，并设置数据库的统计信息收集级别。

Basic: 不会自动收集数据库的计时系统统计信息

Typical和all：会自动收集数据库的计时系统统计信息

84. You are using flat files as the data source for one of your data warehousing applications. You plan to move

the data from the flat file structures to an Oracle database to optimize the application performance. In your

database you have clustered tables. While migrating the data, you want to have minimal impact on the

database performance and optimize the data load operation. Which method would you use to load data into

Oracle database?

A) use the external table population

B) use the Oracle Data Pump export and import utility

C) use the conventional path data load of SQL*Loader utility

D) use the direct path data load of Oracle export and import utility

答案：C

解析：

你正在使用一个简单的文件作为你的应用的数据源，你打算将这些数据从文件里导入到数据库里，以此优化应用程序的性能。你已经收集好了库表。在迁移数据的时候，你想尽可能不影响数据库的性能。
你会使用哪种方法将数据导入到库里？

SQL*LOADER的基本特点：

1）能装入不同数据类型文件及多个数据文件的数据（from the flat file structures to an Oracle database）

2）可装入固定格式，自由定界以及可度长格式的数据

3）可以装入二进制，压缩十进制数据

4）一次可对多个表装入数据

5）连接多个物理记录装到一个记录中

6）对一单记录分解再装入到表中

7）可以用数对制定列生成唯一的KEY

8）可对磁盘或磁带数据文件装入制表中

9）提供装入错误报告

10）可以将文件中的整型字符串，自动转成压缩十进制并装入列表中。

85. You have a large amount of historical data in an operating system file. Some analysts in your organization

need to query this data. The file is too large to load into your current database. Which is the most effective

method to accomplish the task?

A) Upgrade the hardware/memory to accommodate the data.

B) Load the data into your database by using the PARALLEL clause.

C) Give analysts DBA privilege, so that they can query DBA_EXTERNAL_TABLES.

D) Use an external table so you can have the metadata available in your database, but leave the data in the operating system files.

答案：D

解析：外部表注意事项：

86. Which two statements are true about the primary key constraint in a table? (Choose two.)

A) It is not possible to disable the primary key constraint.

B) It is possible to have more than one primary key constraint in a single table.

C) The primary key constraint can be referred by only one foreign key constraint.

D) The primary key constraint can be imposed by combining more than one column.

E) The non-deferrable primary key constraint creates an unique index on the primary key column if it is not already indexed.

答案：DE

解析: 可以综合多个字段建立联合主键，所以答案D正确。
主键可以理解为唯一索引+非空约束，答案E正确。

关于约束的延迟（deferrable）的含义，有两种，一种是defered（延迟检查，即Update或Insert语句执行后不立即进行约束检查，而是在发出Commit命令时采取检测是否符合约束。）
另一种是Immediate（立即检查，即Update或Insert语句执行后立即进行约束检查，发现不满足约束，立即报错）

A →以下语句可以无效化主键，所以选项A错误。
ALTER TABLE policies DISABLE PRIMARY KEY;
B →一个表最多只能有一个主键。
C →主键与参照外键的关系为1：N

87. You are working on the 24X7 database with high transaction volume, to ensure faster instance recovery on

your database you set the FAST_START_MTTR_TARGET initialization parameter to a very low value. What

effect it will have on the database?

A) The database performance would be enhanced.

B) The redo log files would be get filled more frequently.

C) The overall database performance would be degraded.

D) The mean time to recover (MTTR) would be increased.

答案：C

解析：Enhance 提高 degrade降低

fast_start_mttr_target，定义了数据块崩溃后所需要的实例恢复的时间

设置此参数的时候要综合考虑系统的IO，容量以及CPU等信息，要在系统性能和故障恢复时间之间做好平衡（成反比）

将此参数设置成0时将禁用 fast-start checkpointing，这样能减小系统负载但同时会增加系统的恢复时间。如果fast_start_io_target or log_checkpoint_interval被指定，他们会自动覆盖由fast_start_mttr_target参数计算出来的值。

88. Data files of which three tablespaces can be recovered by performing an open recovery? (Choose three.)

A) TEMP

B) UNDO

C) INDEX

D) SYSAUX

E) SYSTEM

答案：ACD

解析：open recovery是指单个数据文件损坏的回复，至少得表空间可以offline或者datafile可以offline的才可能在db处于open模式下回复.

89. View the Exhibit.

Your Oracle 10g database has 6 tablespaces in which:

-TEMP is the default temporary tablespace

- UNDOTBS1 is the default undo tablespace

- USERS is the default permanent tablespace

In this database, which three tablespaces can be made offline? (Choose three.)

A) TEMP

B) PROD

C) USERS

D) SYSAUX

E) SYSTEM

F) UNDOTBS1

答案：BCD

解析：SYSAUX表空间是可以被OFFLINE，不能read only,但是system、undo和temp不行,why?

SQL> alter tablespace sysaux offline;

表空间已更改。

SQL> alter tablespace temp offline;

第 1 行出现错误:

ORA-03217: 变更 TEMPORARY TABLESPACE 无效的选项

SQL> alter tablespace system offline;

第 1 行出现错误:

ORA-01541: 系统表空间无法脱机; 如有必要请关闭

90. The HR user creates a view with this command:

SQL> CREATE VIEW emp_v AS SELECT * FROM scott.emp;

Now HR wants to grant the SELECT privilege on the EMP_V view to the JIM user.

Which statement is true in this scenario?

A) HR can grant the privilege to JIM but without GRANT OPTION.

B) HR can grant the privilege to JIM because HR is the owner of the view.

C) SCOTT has to grant the SELECT privilege on the EMP table to JIM before this operation.

D) HR needs the SELECT privilege on the EMP table with GRANT OPTION from SCOTT for this operation.

答案：D

解析：HR用户根据scott用户的emp表建立了一个视图，他想把该视图的select权限赋予JIM用户，他需要有emp表的with GRANT OPTION才能这么做

With admin option 系统权限

With grant option 对象权限

91. You executed the following command to back up your control file:

ALTER DATABASE BACKUP CONTROLFILE TO TRACE;

Which initialization parameter is used to specify the location of the trace file?

A) USER_DUMP_DEST

B) CORE_DUMP_DEST

C) TRACE_DUMP_DEST

D) BACKUP_DUMP_DEST

E) BACKGROUND_DUMP_DEST

答案：A

解析：当使用该命令ALTER DATABASE BACKUP CONTROLFILE TO TRACE后可以在USER_DUMP_DEST中找到该trace文件(指由用户自己跟踪的文件位置)

92. You work as a database administrator for Supportcenter.cn. You determine that archiving was not successful in one

of the destinators. You want to check the alert log file for more information on this.

Which initialization parameter gives you the location of the alert log file?

A. USER_DUMP_DEST

B. CORE_DUMP_DEST

C.ALERT_LOG_DEST

D.ALERT_DUMP_DEST

E.TRACE_DUMP_DEST

F.BACKGROUND_DUMP_DEST

答案：F

解析：An alert file in the directory specified by BACKGROUND_DUMP_DEST logs significant database events and messages.

93. The junior DBA in your organization has accidentally deleted the alert log file. What will you do to create new alert log file?

A) Create the new text file file as ALERT.LOG.

B) You have to recover the alert log file from the valid backup.

C) Change the value for the BACKGROUND_DUMP_DEST parameter.

D) No action required.The file would be created automatically by the instance.

答案：D

解析：不小心删除alert文件没有关系，数据库会自己自动重建

94. Your database is started by using the server parameter file (SPFILE). You issued this command to change

the value of the LOG_BUFFER initialization parameter:

ALTER SYSTEM SET LOG_BUFFER=24M SCOPE=BOTH;

What would be the outcome of this command?

A) The command would return an error because LOG_BUFFER is a static parameter.

B) The parameter value would be changed and it would come into effect immediately.

C) You need to restart the database so that parameter changes can come into effect.

D) The command would succeed only if initialization parameter LOG_ARCHIVE_MAX_PROCESS is set to value 2.

答案：A

解析：LOG_BUFFER是个静态参数，只能scope=spfile，修改完后重启数据库才能生效

95. Which two statements regarding archive log destinations are true? (Choose two.)

A) A maximum of 10 destinations can be specified.

B) The archive logs must be written to all the destinations.

C) The archive log files can be written only to local destinations.

D) The archiving information can be traced to the alert log file whenever the archiving to a destination is successful.

E) The number of archiving destinations must be equal to the number of archive processes (ARCn).

答案：AD

解析：SQL> show parameter archive

log_archive_dest_10 可以看到最大10个目的地

在使用LOG_ARCHIVE_DEST_n 参数时，可以将目标指定为强制(mandatory) 或可选(optional)
• MANDATORY 表示必须成功完成归档到该目标的操作才可以覆盖联机重做日志文件。
• OPTIONAL 表示即使联机重做日志文件尚未成功地归档到该目标，也可以重新使用。这是缺省设置。

B不正确

The number of archiving processed must be relevant to the parameter value of LOG_ARCHIVE_MAX_PROCESSES.The default value of this parameter is 2.The actual number of archiver processes in use may vary subsequently based on archive workload. So,Answer E is worng.

96. On which three can you use Recovery Manager (RMAN) to perform incremental backup? (Choose three.)

A) data files

B) control files

C) tablespaces

D) password file

E) parameter file

F) whole database

G) flashback log file

H) archived log files

I) change tracking file

答案：ACF

解析：rman可以在datafile 、tablespaces和整个数据库做增量备份

97. You execute the following set of commands to create a database user and to grant the system privileges in your production environment.

SQL> CREATE USER user01

IDENTIFIED BY oracle

DEFAULT TABLESPACE tbs1

TEMPORARY TABLESPACE temp

PROFILE default

SQL> GRANT create session, create table TO user01;

While executing the command to create a table, the user gets the following error message and the CREATE

TABLE.. command fails.

ERROR at line 1:

ORA-01950: no privileges on tablespace

What could be the possible reason for this error message?

A) The tablespace TBS1 is full.

B) The user is not the owner of the SYSTEM tablespace.

C) The user does not have quota on the TBS1 tablespace.

D) The user does not have sufficient system privileges to create table in the TBS1 tablespace.

E) The user does not have sufficient privileges to create table on the default permanent tablespace.

答案：C

解析：

ORA-01950: no privileges on tablespace "string"

Cause: User does not have privileges to allocate an extent in the specified tablespace.

Action: Grant the user the appropriate system privileges or grant the user space resource on the tablespace.

正常grant了resource之后，unlimited tablespace系统权限就被grant了，如果没有unlimited tablespace权限，就需要通过tbs quota来控制

98. The user SCOTT executes the following command successfully to increase the salary values in one of his

sessions:

SQL> UPDATE emp SET sal=sal*1.15 WHERE deptno=20;

Before SCOTT ends the transaction, user HR who has the privileges on EMP table executes a query to fetch

the salary details but finds the old salary values instead of the increased values.

Why does HR still see the old data?

A) because of redo data from redo log file

B) because of data from database buffer cache

C) because of data from a temporary tablespace

D) because of undo data from the undo tablespace

答案：D

解析：在一个update执行后，如果没有Committed，那么会在undo 缓存中建立一个原数据的前镜像，如果这时候查询还会是原来的数据

99. You specified segment space management as automatic for a tablespace. What effect would this have on space management?

A) Extents would be managed by the freelists.

B) The segment would be managed by bitmaps.

C) The segment would be managed by the freelists.

D) Free space would be managed by the data dictionary

答案：B

解析：

段空间是自动管理，就意味着段空间是有位图管理的本地管理的表空间：在表空间中通过位图管理区。位图中的每一位对应一个块或一组块。分配区或为重新利用空间而释放区后，Oracle 服务器通过更改位图值来显示块的新状态。

100. Which two statements about Flashback Query are true? (Choose two.)

A) It is generated by using the redo log files.

B) It helps in row-level recovery from user errors.

C) It can be performed to recover ALTER TABLE statements

D) It fails when undo data pertaining to the transaction is overwritten.

E) The database has to be opened with the resetlogs option after performing Flashback Query.

答案;BD

解析：

Flashback Query可以帮助用户解决行级别的错误。是根据undo data来闪回的，undo retention=900s,这要看有没有retention guarantee，如果有，15分钟内不会被覆盖。如果没有打开，那得看UNTO有没有可用空间，如果没有就会被覆盖

Flashback database相当一次不完全恢复, 此时必需alter database open resetlogs; 即截断多余的scn,本质还是select file#,checkpoint_change# from v$datafile;

select file#,checkpoint_change# from v$datafile_header,两个结果不一致造成的.

10g支持穿越resetlogs了,即用当前数据库的控制文件(resetlog后的控制文件)加上resetlog之前数据文件的备份,其实只要scn连续就行

但一旦resetlogs后,无法再flashback到之前的时间点了