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。

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> 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。

二、多表导出导入测试

--导出2个测试表（t1,t2）到同一个dmp文件中

SQL> !

[oracle@ora10g ~]$ exp

Export: Release 10.2.0.1.0 - Production on 11 11:08:38 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

Enter array fetch buffer size: 4096 > 8192

Export file: expdat.dmp > t1_t2.dmp

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

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

. . exporting table                             T1     100710 rows exported

Table(T) or Partition(T:P) to be exported: (RETURN to quit) > t2

. . exporting table                             T2          2 rows exported

Table(T) or Partition(T:P) to be exported: (RETURN to quit) >     --指定完所需导出的表后回车退出

Export terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

--删除源表

SQL> drop table t1 purge;

Table dropped.

SQL> drop table t2 purge;

Table dropped.

--执行导入

SQL> !

[oracle@ora10g ~]$ imp

Import: Release 10.2.0.1.0 - Production on 11 11:09:38 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_t2.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 > 

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 >     --有别于第一个单表导入的测试，这里如果选择了no，那么就可以分别指定需要导入的部分（t1_t2.dmp中含有t1,t2两个表的逻辑语句，但是现在只导入t1）

Username: zlm

Enter table(T) or partition(T:P) names. Null list means all tables for user    --如果直接回车，就表示导入全部表

Enter table(T) or partition(T:P) name or . if done: t1

Enter table(T) or partition(T:P) name or . if done: .    --只导入t1表，用“.”退出，注意，不是回车了

. importing ZLM‘s objects into ZLM

. importing ZLM‘s objects into ZLM

. . importing table                           "T1"     100710 rows imported

Import terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

SQL> select count(*) from t1;

  COUNT(*)

----------

    100710

SQL> select count(*) from t2;

select count(*) from t2

                     *

ERROR at line 1:

ORA-00942: table or view does not exist

可以看到，只有t1表是导入的，虽然之前导出的是t1,t2两张表到一个dmp文件，但是导入的时候，可以只按照需要的内容单独导入，相当于取了一个子集

SQL> !

[oracle@ora10g ~]$ imp

Import: Release 10.2.0.1.0 - Production on 11 11:10:48 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_t2.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 > 

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"     100710 rows imported

. . importing table                           "T2"          2 rows imported

Import terminated successfully without warnings.

这次直接选择了把整个导出文件的内容到导入到zlm用户，注意后面选项的不同之处

[oracle@ora10g ~]$ exit

exit

SQL> select count(*) from t1;

  COUNT(*)

----------

    201420

SQL> select count(*) from t2;

  COUNT(*)

----------

         2

现在t1,t2表都有数据了，不同的是，由于刚才用了ingore error的方式把t1表导出了2次，所以t1表中成了20W行

三、按用户导出导入测试

这是导入导出中用的最多的一种方式，因此在使用交互方式的时候，默认就是采用了这种方式

SQL> !

[oracle@ora10g ~]$ exp

Export: Release 10.2.0.1.0 - Production on 11 11:11:42 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 > zlm.dmp

(1)E(ntire database), (2)U(sers), or (3)T(ables): (2)U > --按用户导出是默认的方式，直接回车即可

Export grants (yes/no): yes > 

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 users ...

User to be exported: (RETURN to quit) > zlm

User to be exported: (RETURN to quit) >     --指定完需要导出的用户zlm后，直接回车退出配置模式，开始导出

. exporting pre-schema procedural objects and actions

. exporting foreign function library names for user ZLM 

. exporting PUBLIC type synonyms

. exporting private type synonyms

. exporting object type definitions for user ZLM 

About to export ZLM‘s objects ...

. exporting database links

. exporting sequence numbers

. exporting cluster definitions

. about to export ZLM‘s tables via Conventional Path ...

. . exporting table                             T1     201420 rows exported

. . exporting table                             T2          2 rows exported

. exporting synonyms

. exporting views

. exporting stored procedures

. exporting operators

. exporting referential integrity constraints

. exporting triggers

. exporting indextypes

. exporting bitmap, functional and extensible indexes

. exporting posttables actions

. exporting materialized views

. exporting snapshot logs

. exporting job queues

. exporting refresh groups and children

. exporting dimensions

. exporting post-schema procedural objects and actions

. exporting statistics

Export terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

--删除源表，并删除用户zlm

SQL> select count(*) from t1;

  COUNT(*)

----------

    201420

SQL> select count(*) from t2;

  COUNT(*)

----------

         2

SQL> drop table t1 purge;

Table dropped.

SQL> drop table t2 purge;

Table dropped.

SQL> drop user zlm cascade;

drop user zlm cascade

*

ERROR at line 1:

ORA-01940: cannot drop a user that is currently connected

SQL> disc

Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production

With the Partitioning, OLAP and Data Mining options

SQL> conn /as sysdba

Connected.

SQL> drop user zlm cascade;

User dropped.

SQL> !

[oracle@ora10g ~]$ imp

Import: Release 10.2.0.1.0 - Production on 11 11:14:39 2014

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

Username: zlm

Password: 

IMP-00058: ORACLE error 1017 encountered    --由于zlm用户已经不存在，因此报错

ORA-01017: invalid username/password; logon deniedUsername: system    --以system用户登录执行导入

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 > zlm.dmp

Enter insert buffer size (minimum is 8192) 30720> 

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

Warning: the objects were exported by ZLM, not by you

import done in ZHS16GBK character set and AL16UTF16 NCHAR character set

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

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 > 

Username: zlm

Enter table(T) or partition(T:P) names. Null list means all tables for user

Enter table(T) or partition(T:P) name or . if done: 

. importing ZLM‘s objects into SYSTEM

. . importing table                           "T1"     201420 rows imported

IMP-00015: following statement failed because the object already exists:

 "CREATE TABLE "T2" ("OBJECT_NAME" VARCHAR2(128), "SUBOBJECT_NAME" VARCHAR2(3"

 "0), "OBJECT_ID" NUMBER, "DATA_OBJECT_ID" NUMBER, "OBJECT_TYPE" VARCHAR2(19)"

 ", "CREATED" DATE, "LAST_DDL_TIME" DATE, "TIMESTAMP" VARCHAR2(19), "STATUS" "

 "VARCHAR2(7), "TEMPORARY" VARCHAR2(1), "GENERATED" VARCHAR2(1), "SECONDARY" "

 "VARCHAR2(1))  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 STORAGE(INITIAL"

 " 65536 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)                  "

 "LOGGING NOCOMPRESS"

Import terminated successfully with warnings.

[oracle@ora10g ~]$ exit

exit

虽然是按照用户的方式导出的，但导入之前，还是必须要有相同的用户存在，删除用户以后，是无法进行导入的

--重新创建回zlm用户

SQL> create user zlm identified by zlm;

User created.

SQL> grant dba to zlm;

Grant succeeded.

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

USERNAME                       DEFAULT_TABLESPACE

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

ZLM                            USERS    --重新创建用户后，没有专门指定缺省表空间，就使用整个数据库的缺省表空间USERS

SQL> !

[oracle@ora10g ~]$ imp

Import: Release 10.2.0.1.0 - Production on 11 11:17:40 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 > zlm.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 > 

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 > 

Username: zlm

Enter table(T) or partition(T:P) names. Null list means all tables for user

Enter table(T) or partition(T:P) name or . if done: 

. importing ZLM‘s objects into ZLM

. . importing table                           "T1"     201420 rows imported

. . importing table                           "T2"          2 rows imported

Import terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

导入成功了，zlm用户的所有对象都被导入了，即完成了对用户的逻辑恢复

SQL> select count(*) from t1;

select count(*) from t1

                     *

ERROR at line 1:

ORA-00942: table or view does not exist

SQL> show user

USER is "SYS"

SQL> conn zlm/zlm

Connected.

SQL> select count(*) from t1;

  COUNT(*)

----------

    201420

SQL> select count(*) from t2;

  COUNT(*)

----------

         2

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

USERNAME                       DEFAULT_TABLESPACE

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

ZLM                            USERS

SQL> set line 130

SQL> select owner,table_name,tablespace_name from dba_tables where owner=‘ZLM‘;

OWNER                          TABLE_NAME                     TABLESPACE_NAME

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

ZLM                            T1                             ZLM

ZLM                            T2                             ZLM

尽管zlm用户的默认表空间是USERS，但是用imp导入后的表还是会去找原来的表空间进行恢复，即“ZLM”，那么我们把原来的表空间也删除掉，会怎么样呢？

--删除ZLM表空间后测试恢复情况

SQL> drop tablespace zlm including contents;

Tablespace dropped.

SQL> select ts#,name from v$tablespace;

       TS# NAME

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

         0 SYSTEM

         1 UNDOTBS1

         2 SYSAUX

         4 USERS

         6 EXAMPLE

         3 TEMP

6 rows selected.

SQL> col name for a45

SQL> select file#,name from v$datafile;

     FILE# NAME

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

         1 /u01/app/oracle/oradata/ora10g/system01.dbf

         2 /u01/app/oracle/oradata/ora10g/undotbs01.dbf

         3 /u01/app/oracle/oradata/ora10g/sysaux01.dbf

         4 /u01/app/oracle/oradata/ora10g/users01.dbf

         5 /u01/app/oracle/oradata/ora10g/example01.dbf

尽管没有使用including contents and datafiles，数据文件还是一起被删除了

SQL> !

[oracle@ora10g ~]$ imp

Import: Release 10.2.0.1.0 - Production on 11 11:25:57 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 > zlm.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 > 

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

. importing ZLM‘s objects into ZLM

. . importing table                           "T1"     201420 rows imported

. . importing table                           "T2"          2 rows imported

Import terminated successfully without warnings.

[oracle@ora10g ~]$ exit

exit

SQL> select count(*) from t1;

  COUNT(*)

----------

    201420

SQL> select count(*) from t2;

  COUNT(*)

----------

         2

SQL> select owner,table_name,tablespace_name from dba_tables where owner=‘ZLM‘;

OWNER                          TABLE_NAME                     TABLESPACE_NAME

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

ZLM                            T2                             USERS

ZLM                            T1                             USERS

当我们把原来zlm用户导出时的表空间ZLM删除以后再倒入，此时会发现imp会把用户导到数据库缺省的USERS表空间上去，基于这种原理，当我们做逻辑导入导出的时候，尽量保持源端与目标端有相同的环境，当然还包括字符集（这里没有做测试）等。否则在导入数据后，可能会产生意外地状况，比方说源库的表空间是很大的，但是由于在目标库中没有创建相应的表空间，默认放到了USERS表空间中，环境和源库产生了不同，可能导入的时候就直接报错了。当然了，字符集更是一个要注意的问题。

四、按全库导出

全库导出很简单，在选择导出对象的时候选择Entire Database就可以了

[oracle@ora10g ora10g]$ pwd

导出文件很小，只有108M，而实际的数据库中的数据文件有1.2G

总结：

exp/imp通常在Oracle 8i/9i等早期的版本中用得较多，到了10g以后基本全面被数据库泵（Data Pump）取代,即expdp/impdp，虽然说已经是过时的技术，但作为DBA也不能完全不了解，因为和数据泵还是有异曲同工之处的，只是数据泵的功能更强大了。本篇实验采用了一个最不实用的方法来演示exp/imp的使用方法，即：交互方式，该方式可支配的参数非常少，如，不能指定log，feedback等参数，也不能指定按条件进行导出，且每次使用起来都要一步步确认非常多的步骤，非常繁琐，不推荐使用，即便要使用，也推荐采用另外两种方式：1.命令行模式、2.参数文件模式（推荐）。