1.1 TRANSFORM适用场景 导入和导出的时候，有些表空间不一样。比如导出的时候该对象是在A表空间，导入到另一个库没有表空间A就会报错。但是使用这个参数就会正常导入，该对象会存储在该用户下的默认表空间中。
1.2 语法
TRANSFORM = transform_name:value[:object_type]
object_type是可选的，如果不指定object_type，那么则指定导入的所有有效的对象。
TRANSFORM对下面对象有效：CLUSTER, CONSTRAINT, INDEX, ROLLBACK_SEGMENT, TABLE, and TABLESPACE.
1.3 transform_name：SEGMENT_ATTRIBUTES 在官方文档中有很详细的介绍，这里我只介绍一个SEGMENT_ATTRIBUTES的参数值。
1.4 SEGMENT_ATTRIBUTES：value值 值：Y|N
Y：默认值，表示这个段的属性(物理属性，存储属性，表空间和logging)都将被包含在DDL的语句中。
N:表示这些属性都不会在DDL语句中。意思是导入该对象的时候，不会指定表空间等属性，只是简单的创建一个对象。
2 具体例子
2.1 创建一个新的表空间和表
表空间：
SQL> create tablespace test datafile 'D:/app/zhixin/oradata/orcl/test.dbf' size 50M; Tablespace created.
表：
在SCOTT用户下创建EMPLOYEES表
SQL> CREATE TABLE "SCOTT"."EMPLOYEES"
2 ( "EMPLOYEE_ID" NUMBER(6,0),
3 "FIRST_NAME" VARCHAR2(20),
4 "LAST_NAME" VARCHAR2(25) CONSTRAINT "EMP_LAST_NAME_NN" NOT NULL ENABLE,
5 "EMAIL" VARCHAR2(25) CONSTRAINT "EMP_EMAIL_NN" NOT NULL ENABLE,
6 "PHONE_NUMBER" VARCHAR2(20),
7 "HIRE_DATE" DATE CONSTRAINT "EMP_HIRE_DATE_NN" NOT NULL ENABLE,
8 "JOB_ID" VARCHAR2(10) CONSTRAINT "EMP_JOB_NN" NOT NULL ENABLE,
9 "SALARY" NUMBER(8,2),
10 "COMMISSION_PCT" NUMBER(2,2),
11 "MANAGER_ID" NUMBER(6,0),
12 "DEPARTMENT_ID" NUMBER(4,0)
13 ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
14 STORAGE(INITIAL 10240 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 121
15 PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
16 TABLESPACE "TEST" ; Table created.
2.2 查看该表的DDL语句
SQL > SELECT dbms_metadata.get_ddl('TABLE','EMPLOYEES','SCOTT') FROM dual;
CREATE TABLE "SCOTT"."EMPLOYEES"
(
"EMPLOYEE_ID" NUMBER(6,0),
"FIRST_NAME" VARCHAR2(20),
"LAST_NAME" VARCHAR2(25) CONSTRAINT "EMP_LAST_NAME_NN" NOT NULL ENABLE,
"EMAIL" VARCHAR2(25) CONSTRAINT "EMP_EMAIL_NN" NOT NULL ENABLE,
"PHONE_NUMBER" VARCHAR2(20),
"HIRE_DATE" DATE CONSTRAINT "EMP_HIRE_DATE_NN" NOT NULL ENABLE,
"JOB_ID" VARCHAR2(10) CONSTRAINT "EMP_JOB_NN" NOT NULL ENABLE,
"SALARY" NUMBER(8,2),
"COMMISSION_PCT" NUMBER(2,2),
"MANAGER_ID" NUMBER(6,0),
"DEPARTMENT_ID" NUMBER(4,0)
) SEGMENT CREATION DEFERRED
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE( INITIAL 16384 NEXT 16384 MINEXTENTS 1 MAXEXTENTS 121 PCTINCREASE 50 FREELISTS 1 FREELIST GROUPS 1
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "TEST"
2.3 导出SCOTT用户
D:/windows 2.7>expdp system/oracle owner=scott dumpfile=scott.dmp logfile=exp_scott.log directory=zhixin
Export: Release 11.2.0.4.0 - Production on Thu Apr 27 10:57:08 2017
Copyright (c) 1982, 2011, Oracle and/or its affiliates.
All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Legacy Mode Active due to the following parameters:
Legacy Mode Parameter: "owner=scott" Location: Command Line, Replaced with: "schemas=scott"
Legacy Mode has set reuse_dumpfiles=true parameter.
Starting "SYSTEM"."SYS_EXPORT_SCHEMA_01": system/******** schemas=scott dumpfile=scott.dmp logfile=exp_scott.log directory=zhixin reuse_dumpfiles=true
Estimate in progress using BLOCKS method...
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 1024 KB
Processing object type SCHEMA_EXPORT/USERP
rocessing object type SCHEMA_EXPORT/SYSTEM_GRANT
Processing object type SCHEMA_EXPORT/ROLE_GRANT
Processing object type SCHEMA_EXPORT/DEFAULT_ROLE
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Processing object type SCHEMA_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/REF_CONSTRAINT
Processing object type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS. .
exported "SCOTT"."ZX" 704.2 KB 2814 rows. .
exported "SCOTT"."DEPT" 5.929 KB 4 rows. .
exported "SCOTT"."EMP" 8.562 KB 14 rows. .
exported "SCOTT"."SALGRADE" 5.859 KB 5 rows. .
exported "SCOTT"."BONUS" 0 KB 0 rows. .
exported "SCOTT"."EMPLOYEES" 0 KB 0 rows
Master table "SYSTEM"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYSTEM.SYS_EXPORT_SCHEMA_01 is: D:/BACKUP/SCOTT.DMP
Job "SYSTEM"."SYS_EXPORT_SCHEMA_01" successfully completed at Thu Apr 27 10:57:28 2017
elapsed 0 00:00:18
D:/windows 2.7>
2.4 删除该表，重新导入
2.4.1 删除表和表空间：
SQL> drop table scott.employees; Table dropped.
SQL> drop tablespace test including contents;
Tablespace dropped.
SQL> desc scott.employees;
ERROR:ORA-04043: object scott.employees does not exist
2.4.2 重新导入EMPLOYEES表：
2.4.2.1 不加TRANSFORM=SEGMENT_ATTRIBUTES:N:table：
看到了报错：提示TEST表空间不存在，无法导入。那么这个时候就需要TRANSFORM出场了。
D:/windows 2.7>impdp scott/tiger DIRECTORY=ZHIXIN DUMPFILE=SCOTT.DMP LOGFILE=imp_scott.log TABLES=EMPLOYEES
Import: Release 11.2.0.4.0 - Production on Thu Apr 27 11:27:07 2017 Copyright (c) 1982, 2011, Oracle and/or its affiliates.
All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SCOTT"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "SCOTT"."SYS_IMPORT_TABLE_01": scott/******** DIRECTORY=ZHIXIN DUMPFILE=SCOTT.DMP LOGFILE=imp_scott.log TABLES=EMPLOYEES
Processing object type SCHEMA_EXPORT/TABLE/TABLE
ORA-39083: Object type TABLE:"SCOTT"."EMPLOYEES" failed to create with error: ORA-00959: tablespace 'TEST' does not exist
Failing sql is:
CREATE TABLE "SCOTT"."EMPLOYEES"
("EMPLOYEE_ID" NUMBER(6,0),
"FIRST_NAME" VARCHAR2(20 BYTE),
"LAST_NAME" VARCHAR2(25 BYTE) CONSTRAINT "EMP_LAST_NAME_NN" NOT NULL ENABLE,
"EMAIL" VARCHAR2(25 BYTE) CONSTRAINT "EMP_EMAIL_NN" NOT NULL ENABLE,
"PHONE_NUMBER" VARCHAR2(20 BYTE),
"HIRE_DATE" DATE CONSTRAINT "EMP_HIRE_DATE_NN" NOT NULL ENABLE,
"JOB_ID" VARCHAR2(10 BYTE) CONSTRAINT
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Job "SCOTT"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at Thu Apr 27 11:27:09 2017 elapsed 0 00:00:01
2.4.2.2 加TRANSFORM=SEGMENT_ATTRIBUTES:N:table： 表没有导进来。重新导
D:/windows 2.7>impdp scott/tiger DIRECTORY=ZHIXIN DUMPFILE=SCOTT.DMP LOGFILE=imp_scott.log TABLES=EMPLOYEES TRANSFORM=SEGMENT_ATTRIBUTES:N:table
Import: Release 11.2.0.4.0 - Production on Thu Apr 27 11:29:32 2017 Copyright (c) 1982, 2011, Oracle and/or its affiliates.
All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Master table "SCOTT"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "SCOTT"."SYS_IMPORT_TABLE_01": scott/******** DIRECTORY=ZHIXIN DUMPFILE=SCOTT.DMP LOGFILE=imp_scott.log TABLES=EMPLOYEES TRANSFORM=SEGMENT_ATTRIBUTES:N:table
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA. . imported "SCOTT"."EMPLOYEES" 0 KB 0 rows
Job "SCOTT"."SYS_IMPORT_TABLE_01" successfully completed at Thu Apr 27 11:29:34 2017 elapsed 0 00:00:01
可以看到成功导入了。。。
2.5 再次查看该表DDL
SQL >SELECT dbms_metadata.get_ddl('TABLE','EMPLOYEES','SCOTT') FROM dual;
CREATE TABLE "SCOTT"."EMPLOYEES" (
"EMPLOYEE_ID" NUMBER(6,0),"FIRST_NAME" VARCHAR2(20),"LAST_NAME" VARCHAR2(25) CONSTRAINT "EMP_LAST_NAME_NN" NOT NULL ENABLE,"EMAIL" VARCHAR2(25) CONSTRAINT "EMP_EMAIL_NN" NOT NULL ENABLE,"PHONE_NUMBER" VARCHAR2(20),"HIRE_DATE" DATE CONSTRAINT "EMP_HIRE_DATE_NN" NOT NULL ENABLE,"JOB_ID" VARCHAR2(10) CONSTRAINT "EMP_JOB_NN" NOT NULL ENABLE,"SALARY" NUMBER(8,2),"COMMISSION_PCT" NUMBER(2,2),"MANAGER_ID" NUMBER(6,0),"DEPARTMENT_ID" NUMBER(4,0) )
SEGMENT CREATION DEFERRED PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
TABLESPACE "USERS"
--可以看到，创建的DDL语句已经变化。现在使用操作系统默认的表空间USERS和一些默认配置。
其实就是相当于执行了这个语句：
CREATE TABLE "SCOTT"."EMPLOYEES" (
"EMPLOYEE_ID" NUMBER(6,0),"FIRST_NAME" VARCHAR2(20),
"LAST_NAME" VARCHAR2(25) CONSTRAINT "EMP_LAST_NAME_NN" NOT NULL ENABLE,
"EMAIL" VARCHAR2(25) CONSTRAINT "EMP_EMAIL_NN" NOT NULL ENABLE,"PHONE_NUMBER" VARCHAR2(20),
"HIRE_DATE" DATE CONSTRAINT "EMP_HIRE_DATE_NN" NOT NULL ENABLE,
"JOB_ID" VARCHAR2(10) CONSTRAINT "EMP_JOB_NN" NOT NULL ENABLE,
"SALARY" NUMBER(8,2),
"COMMISSION_PCT" NUMBER(2,2),
"MANAGER_ID" NUMBER(6,0),
"DEPARTMENT_ID" NUMBER(4,0)
)