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> 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:
以交互方式使用exp/imp的演示
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