使用IMPDP工具完成数据导入时，会按照dump文件中有关的存储的参数信息完成数据的导入。很多情况下我们希望按照被导入用户的默认参数完成数据的导入，此时我们可以使用IMPDP的TRANSFORM参数辅助完成。

1.IMPDP的TRANSFORM参数描述
secooler@secDB /expdp$ impdp help=y
……省略……
TRANSFORM
Metadata transform. to apply to applicable objects.
Valid keywords are: OID, PCTSPACE, SEGMENT_ATTRIBUTES and STORAGE.
……省略……

2.创建一个测试表T
sec@11gR2> create table t (x varchar2(8));

Table created.

sec@11gR2> insert into t values ('secooler');

1 row created.

sec@11gR2> commit;

Commit complete.

3.使用EXPDP生成表T的逻辑备份文件
secooler@secDB /expdp$ expdp sec/sec directory=expdp_dir dumpfile=sec_expdp.dmp logfile=sec_expdp.log tables=t

Export: Release 11.2.0.1.0 - Production on Thu May 13 09:32:44 2010

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Starting "SEC"."SYS_EXPORT_TABLE_01":  sec/******** directory=expdp_dir dumpfile=sec_expdp.dmp logfile=sec_expdp.log tables=t
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 64 KB
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "SEC"."T"                                   5.007 KB       1 rows
Master table "SEC"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SEC.SYS_EXPORT_TABLE_01 is:
  /expdp/sec_expdp.dmp
Job "SEC"."SYS_EXPORT_TABLE_01" successfully completed at 09:32:57

4.生成dump文件中的SQL语句
1）使用SQLFILE参数生成SQL创建语句
secooler@secDB /expdp$ impdp sec/sec directory=expdp_dir dumpfile=sec_expdp.dmp sqlfile=sec_expdp.sql

Import: Release 11.2.0.1.0 - Production on Thu May 13 09:33:23 2010

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Master table "SEC"."SYS_SQL_FILE_FULL_01" successfully loaded/unloaded
Starting "SEC"."SYS_SQL_FILE_FULL_01":  sec/******** directory=expdp_dir dumpfile=sec_expdp.dmp sqlfile=sec_expdp.sql
Processing object type TABLE_EXPORT/TABLE/TABLE
Job "SEC"."SYS_SQL_FILE_FULL_01" successfully completed at 09:33:26

2）查看sec_expdp.sql文件获得SQL创建语句
secooler@secDB /expdp$ cat sec_expdp.sql
-- CONNECT SEC
ALTER SESSION SET EVENTS '10150 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10904 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '25475 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10407 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10851 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '22830 TRACE NAME CONTEXT FOREVER, LEVEL 192 ';
-- new object type path: TABLE_EXPORT/TABLE/TABLE
CREATE TABLE "SEC"."T"
   (    "X" VARCHAR2(8 BYTE)
   ) SEGMENT CREATION IMMEDIATE
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "TBS_SEC_D" ;

可见，此时包含了大量的存储参数及表空间参数。

5.使用TRANSFORM去掉表空间和存储子句
secooler@secDB /expdp$ impdp sec/sec directory=expdp_dir dumpfile=sec_expdp.dmp sqlfile=sec_expdp.sql TRANSFORM=segment_attributes:n

Import: Release 11.2.0.1.0 - Production on Thu May 13 09:34:12 2010

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
Master table "SEC"."SYS_SQL_FILE_FULL_01" successfully loaded/unloaded
Starting "SEC"."SYS_SQL_FILE_FULL_01":  sec/******** directory=expdp_dir dumpfile=sec_expdp.dmp sqlfile=sec_expdp.sql TRANSFORM=segment_attributes:n
Processing object type TABLE_EXPORT/TABLE/TABLE
Job "SEC"."SYS_SQL_FILE_FULL_01" successfully completed at 09:34:14

再次查看生成的穿件SQL语句：
secooler@secDB /expdp$ cat sec_expdp.sql
-- CONNECT SEC
ALTER SESSION SET EVENTS '10150 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10904 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '25475 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10407 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '10851 TRACE NAME CONTEXT FOREVER, LEVEL 1';
ALTER SESSION SET EVENTS '22830 TRACE NAME CONTEXT FOREVER, LEVEL 192 ';
-- new object type path: TABLE_EXPORT/TABLE/TABLE
CREATE TABLE "SEC"."T"
   (    "X" VARCHAR2(8 BYTE)
   ) ;

此时生成的表T创建语句非常的简介，没错，就是这么简单。

6.小结
使用TRANSFORM选项可以完成去掉表空间和存储子句的目的，这样我们便可以控制导入时按照目标默认的参数。
我们的目标：所有要完成的任务都要在自己的掌控之中，UNDER CONTROL！

Good luck.

secooler
19.05.12

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