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Q          题目

   

Your database instance is in NOMOUNT state.You select the delete option in the Database Configuration Assistant(DBCA) for your database.

What is the outcome?

A. DBCA is able to delete the services but not the data files.

B. DBCA prompts you to open the database, and then proceeds with the deletion.

C. DBCA is able to delete data files but not the services.

D. DBCA shuts down the instance and deletes the database.


     
A          答案          


Answer：A

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

对于B选项，DBCA并不会提示你打开数据库，只会提示数据库没有挂载（ORA-01507: database not mounted）。

对于C选项，说反了。C和A是矛盾选项。这里的services可以理解为/etc/oratab中的有个数据库的记录。如：

[oracle@OCPLHR ~]$ cat /etc/oratab | tail -n 1

OCPLHR2:/u01/app/oracle/product/11.2.0/dbhome_1:N

对于D选项，在NOMOUNT和MOUNT状态下，DBCA图形界面会关闭数据库实例，删除/etc/oratab中的记录和参数文件（spfile和pfile），但是不会删除数据库文件。但是，DBCA静默方式会直接报错，而不做任何操作。

以上解析针对没有安装grid的环境。

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

 

 

You can also use DBCA to delete a database. When DBCA deletes a database, it shuts down the database instance and then deletes all database files. On the Windows platform, it also deletes associated Windows services.

 

有如下几种方式可以用来删除Oracle数据库：

（1）直接在OS级别调用dbca命令以静默的方式删除数据库。使用DBCA进行删除的数据库必须处于OPEN状态，否则不能删除。如下所示，其中，mydb为数据库名：

dbca -silent -deleteDatabase -sourceDB mydb

当然，使用dbca也可以进行图形界面删除，被删除的数据库也必须处于OPEN状态，否则不能删除。其实，从告警日志中可以看到，在OPEN状态下，DBCA删除数据库的过程是，首先将数据库关闭，然后启动数据库到MOUNT状态，接着执行“ALTER SYSTEM ENABLE RESTRICTED SESSION;”让数据库处于受限模式，最后执行“DROP DATABASE;”删除数据库。在删除数据库完成后，会清理文件/etc/oratab中有关被删除数据库的信息，也会删除与该数据库有关的所有的SPFILE和PFILE文件。

需要注意的是，在安装有grid的主机上，如果当前数据库处于非OPEN状态，那么DBCA图形界面和静默方式不会删除和修改任何文件（/etc/oratab和参数文件）；如果主机上没有安装grid，当前数据库处于非OPEN状态，那么DBCA图形界面会删除与该数据库有关的所有的SPFILE和PFILE文件，但是不会删除数据文件，而DBCA静默方式依然会报错，且不会删除和修改任何文件。

（2）SQL窗口：

ALTER DATABASE CLOSE;

ALTER SYSTEM ENABLE RESTRICTED SESSION;

DROP DATABASE;

或：

STARTUP FORCE MOUNT RESTRICT;

DROP DATABASE;

注意：强烈推荐第1种方式，对于第2种方式，若是在RAC环境中，数据库库需要设置参数CLUSTER_DATABASE为FALSE后才可以执行DROP DATABASE，设置的命令为：ALTER SYSTEM SET CLUSTER_DATABASE=FALSE SID='*' SCOPE=SPFILE;。

 

实验如下：

首先在安装了grid的环境下测试：

[oracle@OCPLHR ~]$ ORACLE_SID=OCPXXT1

[oracle@OCPLHR ~]$ sas

 

SQL*Plus: Release 11.2.0.3.0 Production on Fri Apr 20 15:14:10 2018

 

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

 

 

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, Automatic Storage Management, OLAP, Data Mining

and Real Application Testing options

 

SYS@OCPXXT1> startup force nomount

ORACLE instance started.

 

Total System Global Area  521936896 bytes

Fixed Size                  2229944 bytes

Variable Size             352323912 bytes

Database Buffers          159383552 bytes

Redo Buffers                7999488 bytes

SYS@OCPXXT1> exit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

 

[oracle@OCPLHR ~]$ dbca -silent -deleteDatabase -sourceDB OCPXXT1

ORA-01507: database not mounted

 

[oracle@OCPLHR ~]$

 

 

 

启动到mount状态：

SYS@OCPXXT1> alter database mount;

 

Database altered.

 

SYS@OCPXXT1> exit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

 

[oracle@OCPLHR ~]$ dbca -silent -deleteDatabase -sourceDB OCPXXT1

ORA-01219: database not open: queries allowed on fixed tables/views only

 

 

 

启动到OPEN状态：

[oracle@OCPLHR ~]$ sas

 

SQL*Plus: Release 11.2.0.3.0 Production on Fri Apr 20 15:29:55 2018

 

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

 

 

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

 

SYS@OCPXXT1> alter database open;

 

Database altered.

 

SYS@OCPXXT1> exit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

[oracle@OCPLHR ~]$ dbca -silent -deleteDatabase -sourceDB OCPXXT1

Connecting to database

4% complete

9% complete

14% complete

19% complete

23% complete

28% complete

47% complete

Updating network configuration files

48% complete

52% complete

Deleting instance and datafiles

76% complete

100% complete

Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/OCPXXT1.log" for further details.

[oracle@OCPLHR ~]$

 

 

告警日志：

Fri Apr 20 15:31:06 2018

Shutting down instance (immediate)

Shutting down instance: further logons disabled

Fri Apr 20 15:31:07 2018

Stopping background process CJQ0

Stopping background process QMNC

Stopping background process MMNL

Stopping background process MMON

License high water mark = 4

Stopping Job queue slave processes, flags = 7

Job queue slave processes stopped

All dispatchers and shared servers shutdown

ALTER DATABASE CLOSE NORMAL

Fri Apr 20 15:31:12 2018

SMON: disabling tx recovery

SMON: disabling cache recovery

Fri Apr 20 15:31:12 2018

Shutting down archive processes

Archiving is disabled

Fri Apr 20 15:31:12 2018

ARCH shutting down

ARC3: Archival stopped

Fri Apr 20 15:31:12 2018

ARCH shutting down

ARC2: Archival stopped

Fri Apr 20 15:31:12 2018

ARCH shutting down

ARC1: Archival stopped

Fri Apr 20 15:31:12 2018

ARCH shutting down

ARC0: Archival stopped

Thread 1 closed at log sequence 49

Successful close of redo thread 1

Completed: ALTER DATABASE CLOSE NORMAL

ALTER DATABASE DISMOUNT

Shutting down archive processes

Archiving is disabled

Completed: ALTER DATABASE DISMOUNT

ARCH: Archival disabled due to shutdown: 1089

Shutting down archive processes

Archiving is disabled

ARCH: Archival disabled due to shutdown: 1089

Shutting down archive processes

Archiving is disabled

Fri Apr 20 15:31:14 2018

Stopping background process VKTM

Fri Apr 20 15:31:14 2018

NOTE: Shutting down MARK background process

Fri Apr 20 15:31:18 2018

Instance shutdown complete

Fri Apr 20 15:31:18 2018

Adjusting the default value of parameter parallel_max_servers

from 160 to 135 due to the value of parameter processes (150)

Starting ORACLE instance (normal)

LICENSE_MAX_SESSION = 0

LICENSE_SESSIONS_WARNING = 0

Picked latch-free SCN scheme 3

Using LOG_ARCHIVE_DEST_1 parameter default value as USE_DB_RECOVERY_FILE_DEST

WARNING: db_recovery_file_dest is same as db_create_file_dest

Autotune of undo retention is turned on.

IMODE=BR

ILAT =27

LICENSE_MAX_USERS = 0

SYS auditing is disabled

Starting up:

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options.

ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1

System name:    Linux

Node name:      OCPLHR

Release:        2.6.18-194.el5

Version:        #1 SMP Tue Mar 16 21:52:39 EDT 2010

Machine:        x86_64

VM name:        VMWare Version: 6

Using parameter settings in server-side spfile /u01/app/oracle/product/11.2.0/dbhome_1/dbs/spfileOCPXXT1.ora

System parameters with non-default values:

  processes                = 150

  memory_target            = 500M

  control_files            = "/u01/app/oracle/oradata/OCPXXT1/control01.ctl"

  control_files            = "/u01/app/oracle/oradata/OCPXXT1/control02.ctl"

  db_block_size            = 8192

  compatible               = "11.2.0.0.0"

  db_create_file_dest      = "+DATA"

  db_recovery_file_dest    = "+DATA"

  db_recovery_file_dest_size= 4122M

  undo_tablespace          = "UNDOTBS1"

  remote_login_passwordfile= "EXCLUSIVE"

  db_domain                = ""

  dispatchers              = "(PROTOCOL=TCP) (SERVICE=OCPASM1XDB)"

  local_listener           = "LISTENER_OCPASM1"

  job_queue_processes      = 1000

  audit_file_dest          = "/u01/app/oracle/admin/OCPASM1/adump"

  audit_trail              = "DB"

  db_name                  = "OCPXXT1"

  open_cursors             = 300

  diagnostic_dest          = "/u01/app/oracle"

Fri Apr 20 15:31:19 2018

PMON started with pid=2, OS id=32329

Fri Apr 20 15:31:19 2018

PSP0 started with pid=3, OS id=32331

Fri Apr 20 15:31:20 2018

VKTM started with pid=4, OS id=32333 at elevated priority

VKTM running at (1)millisec precision with DBRM quantum (100)ms

Fri Apr 20 15:31:20 2018

GEN0 started with pid=5, OS id=32337

Fri Apr 20 15:31:20 2018

DIAG started with pid=6, OS id=32339

Fri Apr 20 15:31:20 2018

DBRM started with pid=7, OS id=32341

Fri Apr 20 15:31:20 2018

DIA0 started with pid=8, OS id=32343

Fri Apr 20 15:31:20 2018

MMAN started with pid=9, OS id=32345

Fri Apr 20 15:31:20 2018

DBW0 started with pid=10, OS id=32347

Fri Apr 20 15:31:20 2018

LGWR started with pid=11, OS id=32349

Fri Apr 20 15:31:20 2018

CKPT started with pid=12, OS id=32351

Fri Apr 20 15:31:20 2018

SMON started with pid=13, OS id=32353

Fri Apr 20 15:31:20 2018

RECO started with pid=14, OS id=32355

Fri Apr 20 15:31:20 2018

MMON started with pid=15, OS id=32357

Fri Apr 20 15:31:20 2018

MMNL started with pid=16, OS id=32359

starting up 1 dispatcher(s) for network address '(ADDRESS=(PARTIAL=YES)(PROTOCOL=TCP))'...

starting up 1 shared server(s) ...

ORACLE_BASE from environment = /u01/app/oracle

Fri Apr 20 15:31:20 2018

ALTER DATABASE   MOUNT

Successful mount of redo thread 1, with mount id 4088229128

Database mounted in Exclusive Mode

Lost write protection disabled

Completed: ALTER DATABASE   MOUNT

Fri Apr 20 15:31:25 2018

Stopping background process MMNL

Stopping background process MMON

Starting background process MMON

Fri Apr 20 15:31:27 2018

MMON started with pid=15, OS id=32403

Starting background process MMNL

Fri Apr 20 15:31:27 2018

MMNL started with pid=16, OS id=32405

ALTER SYSTEM enable restricted session;

DROP DATABASE

Deleted file /u01/app/oracle/oradata/OCPXXT1/system01.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/sysaux01.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/undotbs101.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/users01.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/example01.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/testasm01.dbf

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo01_1.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo01_2.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo02_1.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo02_2.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo03_1.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/redo03_2.log

Deleted file /u01/app/oracle/oradata/OCPXXT1/temp01.dbf

Deleted file /u01/app/oracle/product/11.2.0/dbhome_1/dbs/snapcf_OCPXXT1.f

Shutting down archive processes

Archiving is disabled

所以，经过测试，若安装了grid，则使用DBCA进行删除的数据库必须处于OPEN状态，否则不能删除。另外，需要注意的是，在没有安装grid的主机上删除数据库时，报错信息不一样，如下所示：

 

 

 

 

告警日志：

Fri Apr 20 16:52:54 2018

Shutting down instance (immediate)

Shutting down instance: further logons disabled

Stopping background process MMNL

Stopping background process MMON

License high water mark = 2

All dispatchers and shared servers shutdown

ALTER DATABASE CLOSE NORMAL

ORA-1507 signalled during: ALTER DATABASE CLOSE NORMAL...

ARCH: Archival disabled due to shutdown: 1089

Shutting down archive processes

Archiving is disabled

ARCH: Archival disabled due to shutdown: 1089

Shutting down archive processes

Archiving is disabled

Fri Apr 20 16:52:59 2018

Stopping background process VKTM

Fri Apr 20 16:53:01 2018

Instance shutdown complete

  查看数据文件，依然存在。只是删除了spfile和pfile，且清除了/etc/oratab中的信息。OPEN状态下删除数据库和安装了grid的主机是一样的。

  






OCP最新题库解析历史连接（052）  

http://mp.weixin.qq.com/s/bUgn4-uciSndji_pUbLZfA


DB笔试面试历史连接  

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