以交互方式使用exp/imp的演示

总所周知,用exp/imp对数据库进行逻辑备份,包括表,用户,整个数据库,我们通常所熟悉的是使用命令行指定参数的方式来做的。下面我来演示一下不太常用的以交互方式的操作,操作很简单,就是只要输入exp/imp的命令,以交互方式提供导入导出所需的参数来完成。虽然这种方式没有实际的应用意义,但作为Oracle提供的一种方法,我们也是有必要熟悉一下的。

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----------------------------Expdp/Impdp的相关参数----------------------------

 

环境:Oracle 10.2.0.1/Linux Red Hat 5.3

 

一、单表导出导入测试

 

--创建测试表

[oracle@ora10g ~]$ sqlplus zlm/zlm

SQL> select username,default_tablespace from dba_users where username='ZLM';

 

USERNAME                       DEFAULT_TABLESPACE

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

ZLM                            ZLM

 

SQL> create table t1 as select * from dba_objects;

 

Table created.

 

SQL> create table t2 as select * from user_objects;

 

Table created.

 

SQL> select count(*) from t1;

 

  COUNT(*)

----------

     50355

 

SQL> select count(*) from t2;

 

  COUNT(*)

----------

         2

 

SQL> !

 

注意,由于之前指定过zlm用户的缺省表空间为ZLM,因此这2个测试表是会创建到ZLM表空间中去的

 

--执行导出t1表

[oracle@ora10g ~]$ exp

 

Export: Release 10.2.0.1.0 - Production on 11 11:04:17 2014

 

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

 

 

Username: zlm

Password: 

 

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

Enter array fetch buffer size: 4096 > 8192

 

Export file: expdat.dmp > t1.dmp    -指定导出的dmp文件名

 

(1)E(ntire database), (2)U(sers), or (3)T(ables): (2)U > t    --可以输入“T”,也可以输入“3”

 

Export table data (yes/no): yes > 

 

Compress extents (yes/no): yes > 

 

Export done in ZHS16GBK character set and AL16UTF16 NCHAR character set

 

About to export specified tables via Conventional Path ...

Table(T) or Partition(T:P) to be exported: (RETURN to quit) >     --如果不输入表名直接回车表示会退出的,不导出任何表

 

Export terminated successfully without warnings.

[oracle@ora10g ~]$ exp    --由于刚才直接退出了,再重新导一次

 

Export: Release 10.2.0.1.0 - Production on 11 11:05:00 2014

 

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

 

 

Username: zlm

Password: 

 

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

Enter array fetch buffer size: 4096 > 8192    --指定buffer,默认是4k,这里指定了8k,实际使用时还可以设置更大的值,如1000000,即10M

 

Export file: expdat.dmp > t1.dmp

 

(1)E(ntire database), (2)U(sers), or (3)T(ables): (2)U > 3

 

Export table data (yes/no): yes > 

 

Compress extents (yes/no): yes > 

 

Export done in ZHS16GBK character set and AL16UTF16 NCHAR character set

 

About to export specified tables via Conventional Path ...

Table(T) or Partition(T:P) to be exported: (RETURN to quit) > t1    --指定需要导出的t1测试表

 

. . exporting table                             T1      50355 rows exported

Table(T) or Partition(T:P) to be exported: (RETURN to quit) >     --没有其他想导出的表,就回车退出

 

Export terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

 

--删除测试表t1

SQL> drop table t1 purge;

 

Table dropped.

 

SQL> select count(*) from t1;

select count(*) from t1

                     *

ERROR at line 1:

ORA-00942: table or view does not exist

 

--执行导入t1表

SQL> !

[oracle@ora10g ~]$ imp

 

Import: Release 10.2.0.1.0 - Production on 11 11:06:12 2014

 

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

 

Username: zlm

Password: 

 

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

 

Import file: expdat.dmp > t1.dmp    --指定刚才由exp生成的dmp文件作为导入的源

 

Enter insert buffer size (minimum is 8192) 30720>     --指定insert的buffer,直接回车采用默认值30720

 

Export file created by EXPORT:V10.02.01 via conventional path

import done in ZHS16GBK character set and AL16UTF16 NCHAR character set

List contents of import file only (yes/no): no >    --默认是no,如果选择了yes,那么就没有以下3个选项了

 

Ignore create error due to object existence (yes/no): no > 

 

Import grants (yes/no): yes > 

 

Import table data (yes/no): yes > 

 

Import entire export file (yes/no): no > yes    --由于导出的时候只是对t1表单独的操作,所以选择yes也仅仅是导入t1表而已

 

. importing ZLM's objects into ZLM

. importing ZLM's objects into ZLM

. . importing table                           "T1"      50355 rows imported

Import terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

 

SQL> select count(*) from t1;

 

  COUNT(*)

----------

     50355

 

SQL> !

 

现在表已经成功地被重新导入到数据库中的zlm用户中,相当于利用了原来对t1表的逻辑备份,对误删除的t1表进行恢复,如果再对已经存在的t1表执行一次导入操作,会发生什么情况呢?

 

[oracle@ora10g ~]$ imp

 

Import: Release 10.2.0.1.0 - Production on 11 11:07:12 2014

 

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

 

Username: zlm

Password: 

 

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

 

Import file: expdat.dmp > t1.dmp

 

Enter insert buffer size (minimum is 8192) 30720> 

 

Export file created by EXPORT:V10.02.01 via conventional path

import done in ZHS16GBK character set and AL16UTF16 NCHAR character set

List contents of import file only (yes/no): no > yes

(选yes就没有了刚才的3个选项了)

Import entire export file (yes/no): no > yes    --依然是选择导入整个导出文件t1.dmp(即:文件中仅有t1表的逻辑语句)

 

. importing ZLM's objects into ZLM

. importing ZLM's objects into ZLM

 "CREATE TABLE "T1" ("OWNER" VARCHAR2(30), "OBJECT_NAME" VARCHAR2(128), "SUBO"

 "BJECT_NAME" VARCHAR2(30), "OBJECT_ID" NUMBER, "DATA_OBJECT_ID" NUMBER, "OBJ"

 "ECT_TYPE" VARCHAR2(19), "CREATED" DATE, "LAST_DDL_TIME" DATE, "TIMESTAMP" V"

 "ARCHAR2(19), "STATUS" VARCHAR2(7), "TEMPORARY" VARCHAR2(1), "GENERATED" VAR"

 "CHAR2(1), "SECONDARY" VARCHAR2(1))  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRA"

 "NS 255 STORAGE(INITIAL 6291456 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DE"

 "FAULT) TABLESPACE "ZLM" LOGGING NOCOMPRESS"

. . skipping table "T1"                             

 

Import terminated successfully without warnings.   

 

这里虽然提示“无警告地成功地结束了命令”,但并没有执行真正的导入,原因是之前的t1表已经存在,默认如果发生object existance的error,那么导入就会终止,这时候我们可以通过选择“Ignore create error due to object existence (yes/no): no > yes”来解决,这个交互模式中的yes就相当于我们熟悉的命令行中的参数ignore=y,表示使用追加的方式导入,并不会覆盖原来的数据,也不会因为对象已经存在而终止导入

 

[oracle@ora10g ~]$ imp

 

Import: Release 10.2.0.1.0 - Production on 11 11:07:38 2014

 

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

 

Username: zlm

Password: 

 

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

 

Import file: expdat.dmp > t1.dmp

 

Enter insert buffer size (minimum is 8192) 30720> 

 

Export file created by EXPORT:V10.02.01 via conventional path

import done in ZHS16GBK character set and AL16UTF16 NCHAR character set

List contents of import file only (yes/no): no >     --选择no才能出现更多的参数选项,否则直接跳到是否导入整个文件

 

Ignore create error due to object existence (yes/no): no > yes

 

Import grants (yes/no): yes > 

 

Import table data (yes/no): yes > 

 

Import entire export file (yes/no): no > yes

 

. importing ZLM's objects into ZLM

. importing ZLM's objects into ZLM

. . importing table                           "T1"      50355 rows imported

Import terminated successfully without warnings.

 

同样是提示“无警告地成功地结束了命令”,但这次真正导出了t1表,我们看到了“"T1"      50355 rows imported”的字样

 

[oracle@ora10g ~]$ exit

exit

 

SQL> select count(*) from t1;

 

  COUNT(*)

----------

    100710

 

此时表中的数据为10W行,比原来的5W行多了一倍,因为又重复导入了一次,相当于把原来的数据又复制了一份。但要注意,如果表中有主键或者唯一约束的话,这种方式导入是不推荐的,可能会报错,未测试。

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