2017年Oracle认证考试题库

Oracle认证证书只是让雇主了解到来应聘的人通过了Oracle数据库方面的技术考试。下面是关于Oracle认证考试题库，欢迎大家参考!

QUESTION 19

You executed the following command to create a password file in the database server:

$ orapwd file = orapworcl entries = 5 ignorecase=N

Which statement describes the purpose of the above password file?

A. It records usernames and passwords of users when granted the DBA role

B. It contains usernames and passwords of users for whom auditing is enabled

C. It is used by Oracle to authenticate users for remote database administrator

D. It records usernames and passwords of all users when they are added to OSDBA or OSOPER operating groups

Correct Answer: C

【考点分析】sys用户身份验证,口令文件

【题意简述】创建口令文件的目的是?

【原理概念】

sysdba身份远程连接数据库时,使用口令文件来验证授权用户.

【答案剖析】

A: 错误,授予用户sysdba身份时,用户口令记录在口令文件,不是dba角色.

B: 错误,审计用户的密码不会记录在口令文件.

C: 正确, sysdba身份远程连接数据库时,使用口令文件来验证授权用户.

D: 错误,把用户添加到操作系统OSDBA 或OSOPER组不会把口令记录到口令文件.

QUESTION 20

SQL> CREATE BIGFILE TABLESPACE MRKT

DATAFILE '/u01/app/oracle/oradata/orcl/mrkt.dbf' size 10M LOGGING 3 EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;

Tablespace created.

SQL> ALTER DATABASE DEFAULT TABLESPACE MRKT;

Database altered.

Which two statements are true regarding the MRKT tablespace? (Choose two.)

A. No more data files can be added to the tablespace.

B. Segment space is managed by free lists in the tablespace.

C. A user created without being assigned a default tablespace uses this tablespace.

D. The tablespace can be dropped with the current setting with segments present in it.

Correct Answer: AC

【考点分析】大文件和小文件表空间区别, 数据默认表空间,段空间管理方式

【题意简述】创建大文件表空间MRKT为数据库的默认表空间,哪个描述是正确的?

【原理概念】

创建BIGFILE时,oracle自动创建本地管理和自动段空间管理(ASSM)的`表空间.

Oracle Database automatically creates a locally managed tablespace with automatic segment space management.

Use this clause to determine whether the tablespace is a bigfile or smallfile tablespace.

This clause overrides any default tablespace type setting for the database.

· A bigfiletablespace containsonly one datafile or tempfile, which can contain up to approximately 4 billion(232) blocks.大文件表空间只能包含一个数据文件或临时文件.

· A smallfiletablespace is atraditional Oracle tablespace, which can contain 1022 datafiles or tempfiles,each of which can contain up to approximately 4 million (222)blocks.

使用大文件表空间的好处:

大文件表空间可以化最小表空间文件数量,从而简化DBA管理,在大型数据库中的表空间可能包含几十或几百个数据文件,随着文件数据的增加,一些数据库参数需要做出相应的调整比如db_files,这个静态参数还要重启数据库才能生效,这都给数据库的维护带来不便,大文件表空间可以解决这个问题.由于文件数量减少,控制文件的空间使用也随之减少,检查点等数据库内部操作需要同步的文件头数量也大大减少.

【实验参考】

(1)创建大文件表空间mrkt

SYS@ENMOEDU> create bigfile tablespace mrkt datafile '/u01/app/oracle/oradata/ENMOEDU/mrkt.dbf' size 10m;

Tablespace created.

(2)查看表空间类型

SYS@ENMOEDU>select tablespace_name,bigfile from dba_tablespaces;

TABLESPACE_NAME BIG

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

SYSTEM NO

SYSAUX NO

TEMP NO

USERS NO

EXAMPLE NO

UNDOTBS2 NO

MRKT YES

(3)添加文件或删除数据库默认表空间会报错

SYS@ENMOEDU> alter tablespace mrkt add datafile '/u01/app/oracle/oradata/ENMOEDU/mrkt01.dbf' size 10m;

alter tablespace mrkt add datafile '/u01/app/oracle/oradata/ENMOEDU/mrkt01.dbf' size 10m

*

ERROR at line 1:

ORA-32771: cannot add file to bigfile tablespace

SYS@ENMOEDU> alter database default tablespace mrkt;

Database altered.

SYS@ENMOEDU> drop tablespace mrkt including contents and datafiles;

drop tablespace mrkt including contents and datafiles

*

ERROR at line 1:

ORA-12919: Can not drop the default permanent tablespace

(4)查看数据库默认创建表空间类型

SYS@ENMOEDU> col PROPERTY_NAME for a20

SYS@ENMOEDU> col PROPERTY_VALUE for a15

SYS@ENMOEDU> col DESCRIPTION for a30

SYS@ENMOEDU>select * from database_properties where property_name='DEFAULT_TBS_TYPE';

PROPERTY_NAME PROPERTY_VALUE DESCRIPTION

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

DEFAULT_TBS_TYPE SMALLFILE Default tablespace type

(5)修改默认表空间类型:

SYS@ENMOEDU> alter database set default bigfile tablespace;

Database altered.

SYS@ENMOEDU> select * from database_properties where property_name='DEFAULT_TBS_TYPE';

PROPERTY_NAME PROPERTY_VALUE DESCRIPTION

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

DEFAULT_TBS_TYPE BIGFILE Default tablespace type

SYS@ENMOEDU> alter database set default smallfile tablespace;

Database altered.

SYS@ENMOEDU> select * from database_properties where property_name='DEFAULT_TBS_TYPE';

PROPERTY_NAME PROPERTY_VALUE DESCRIPTION

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

DEFAULT_TBS_TYPE SMALLFILE Default tablespace type

【答案剖析】

A: 正确,大文件表空间只能包含一个文件;

B: 错误,段空间是用位图方式自动管理的不是通过free lists手工管理;

C: 正确,MRKT是数据库默认表空间,创建用户时不指定默认表空间,则使用数据库默认的;

D: 错误,正在使用的或是数据库默认表空间不能被删除.