Oracle 19c中业务表的列发生变化时使用impdp

适用范围

适用于Oracle 19c

方案概述

生产环境中有需要对业务表的列进行修改，主要是表字段的增加和删除。变更前通过expdp将表导出，字段变更后使用impdp将表数据导入。

当目标表的结构（列的增加、删除、默认值等）与原导出的 DMP 文件不一致时，使用 TABLE_EXISTS_ACTION=TRUNCATE 参数依然可以成功导入数据。

实施步骤

1、准备工作-创建用户

登录到pdb中创建执行数据泵操作的用户

sql 复制代码

--登录到CDB
[oracle@19cdb01 ~]$ sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Tue May 19 14:35:37 2026
Version 19.27.0.0.0
Copyright (c) 1982, 2024, Oracle.  All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.27.0.0.0

Hello
------------------------------------------------
Welcome! you are connected to CDB19C database

CONNAME
--------------------------------------------------------------------------------
CDB$ROOT

SYS@cdb19c(CDB$ROOT)> show pdbs

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 HRPDB                          READ WRITE NO
         6 RCATPDB                        READ WRITE NO
--切换到pdb 
SYS@cdb19c(CDB$ROOT)> alter session set container=HRPDB;

Session altered.
--在HRPDB中创建执行数据泵（expdp/impdp）的用户并授权
SYS@cdb19c(CDB$ROOT)> create user expoer identified by Oracle_2026;

User created.

SYS@cdb19c(CDB$ROOT)> grant connect,resource to expoer;

Grant succeeded.

SYS@cdb19c(CDB$ROOT)> grant EXP_FULL_DATABASE to expoer;

Grant succeeded.

SYS@cdb19c(CDB$ROOT)> grant IMP_FULL_DATABASE to expoer;

Grant succeeded.
--directory IMP_DIR已经提前创建，如果没有创建需要创建directory并保证空间足够，权限正确
SYS@cdb19c(CDB$ROOT)> grant write,read on directory IMP_DIR to expoer;

Grant succeeded.
--修改用户的表空间配额
SYS@cdb19c(CDB$ROOT)> ALTER USER  expoer QUOTA  unlimited ON users;

User altered.

SYS@cdb19c(CDB$ROOT)>

2、创建业务表

登录hr业务用户

sql 复制代码

[oracle@19cdb01 ~]$ sqlplus hr@hrpdb

SQL*Plus: Release 19.0.0.0.0 - Production on Tue May 19 14:41:11 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2024, Oracle.  All rights reserved.


Last Successful login time: Tue Jun 24 2025 03:50:35 +08:00

Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.27.0.0.0

--创建表
HR@hrpdb(HRPDB)> create table emp3 as select * from employees;

Table created.
--验证表
HR@hrpdb(HRPDB)> select count(*) from emp2;

  COUNT(*)
----------
       107

HR@hrpdb(HRPDB)> desc emp2
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                                        NUMBER(6)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 EMAIL                                     NOT NULL VARCHAR2(25)
 PHONE_NUMBER                                       VARCHAR2(20)
 HIRE_DATE                                 NOT NULL DATE
 JOB_ID                                    NOT NULL VARCHAR2(10)
 SALARY                                             NUMBER(8,2)
 COMMISSION_PCT                                     NUMBER(2,2)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)

HR@hrpdb(HRPDB)>

3、执行empdp对emp2 导出

sql 复制代码

expdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 logfile=exp_emp2_20260604.log

[oracle@19cdb01 ~]$ expdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 logfile=exp_emp2_20260604.log

Export: Release 19.0.0.0.0 - Production on Thu Jun 04 10:31:38 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Starting "EXPOER"."SYS_EXPORT_TABLE_01":  expoer/********@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 logfile=exp_emp2_20260604.log
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
Processing object type TABLE_EXPORT/TABLE/TABLE
. . exported "HR"."EMP2"                                 13.75 KB     107 rows
Master table "EXPOER"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for EXPOER.SYS_EXPORT_TABLE_01 is:
  /home/oracle/emp2_20260604.dmp
Job "EXPOER"."SYS_EXPORT_TABLE_01" successfully completed at Thu Jun 04 10:31:55 2026 elapsed 0 00:00:15

4、修改字段进行impdp
场景1：

对emp2表进行字段修改-删除一个字段

sql 复制代码

HR@hrpdb(HRPDB)> ALTER TABLE emp2 drop COLUMN EMAIL;

Table altered.

HR@hrpdb(HRPDB)> desc emp2
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                                        NUMBER(6)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 PHONE_NUMBER                                       VARCHAR2(20)
 COMMISSION_PCT                                     NUMBER(2,2)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)

HR@hrpdb(HRPDB)>

使用impdp导入emp2

使用了参数TABLE_EXISTS_ACTION= TRUNCATE

sql 复制代码

[oracle@19cdb01 ~]$ impdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION= TRUNCATE logfile=impdp_emp2_20260604.log

Import: Release 19.0.0.0.0 - Production on Thu Jun 04 10:34:05 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Master table "EXPOER"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "EXPOER"."SYS_IMPORT_TABLE_01":  expoer/********@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION=TRUNCATE logfile=impdp_emp2_20260604.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Table "HR"."EMP2" exists and has been truncated. Data will be loaded but all dependent metadata will be skipped due to table_exists_action of truncate
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "HR"."EMP2"                                 13.75 KB     107 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
Job "EXPOER"."SYS_IMPORT_TABLE_01" successfully completed at Thu Jun 04 10:34:12 2026 elapsed 0 00:00:06

成功impdp。

场景2：

对emp2表进行字段修改-增加一个字段

sql 复制代码

HR@hrpdb(HRPDB)>  ALTER TABLE emp2 add (address varchar2(30));

Table altered.

HR@hrpdb(HRPDB)> desc emp2
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                                        NUMBER(6)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 PHONE_NUMBER                                       VARCHAR2(20)
 COMMISSION_PCT                                     NUMBER(2,2)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)
 ADDRESS                                            VARCHAR2(30)

HR@hrpdb(HRPDB)>

执行impdp对emp2进行导入（使用了参数TABLE_EXISTS_ACTION= TRUNCATE）

sql 复制代码

impdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION= TRUNCATE logfile=impdp_emp2_202606042.log
[oracle@19cdb01 ~]$ impdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION= TRUNCATE logfile=impdp_emp2_202606042.log

Import: Release 19.0.0.0.0 - Production on Thu Jun 04 10:40:06 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Master table "EXPOER"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "EXPOER"."SYS_IMPORT_TABLE_01":  expoer/********@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION=TRUNCATE logfile=impdp_emp2_202606042.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Table "HR"."EMP2" exists and has been truncated. Data will be loaded but all dependent metadata will be skipped due to table_exists_action of truncate
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "HR"."EMP2"                                 13.75 KB     107 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
Job "EXPOER"."SYS_IMPORT_TABLE_01" successfully completed at Thu Jun 04 10:40:13 2026 elapsed 0 00:00:06

impdp 执行成功。

场景3：

对emp2表进行字段修改-增加一个字段有默认值

sql 复制代码

HR@hrpdb(HRPDB)> alter table emp2 add (userName varchar2(30) default 'HFXF' not null);

Table altered.

HR@hrpdb(HRPDB)> desc emp2
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                                        NUMBER(6)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 PHONE_NUMBER                                       VARCHAR2(20)
 COMMISSION_PCT                                     NUMBER(2,2)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)
 ADDRESS                                            VARCHAR2(30)
 USERNAME                                  NOT NULL VARCHAR2(30)

HR@hrpdb(HRPDB)>

执行impdp对emp2进行导入（使用了参数TABLE_EXISTS_ACTION= TRUNCATE）

sql 复制代码

[oracle@19cdb01 ~]$ impdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION= TRUNCATE logfile=impdp_emp2_202606043.log

Import: Release 19.0.0.0.0 - Production on Thu Jun 04 10:42:50 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Master table "EXPOER"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "EXPOER"."SYS_IMPORT_TABLE_01":  expoer/********@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION=TRUNCATE logfile=impdp_emp2_202606043.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Table "HR"."EMP2" exists and has been truncated. Data will be loaded but all dependent metadata will be skipped due to table_exists_action of truncate
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "HR"."EMP2"                                 13.75 KB     107 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
Job "EXPOER"."SYS_IMPORT_TABLE_01" successfully completed at Thu Jun 04 10:42:54 2026 elapsed 0 00:00:03

impdp执行成功。

场景4：

对emp2表进行字段修改-增加3个字段

sql 复制代码

HR@hrpdb(HRPDB)> ALTER TABLE emp2 add (address4 varchar2(30));

Table altered.
HR@hrpdb(HRPDB)> ALTER TABLE emp2 add (address5 varchar2(30));

Table altered.
HR@hrpdb(HRPDB)> ALTER TABLE emp2 add (address6 varchar2(30));

Table altered.

执行impdp对emp2进行导入（使用了参数TABLE_EXISTS_ACTION= TRUNCATE）

sql 复制代码

[oracle@19cdb01 ~]$ impdp expoer/Oracle_123@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION= TRUNCATE logfile=impdp_emp2_202606043.log

Import: Release 19.0.0.0.0 - Production on Thu Jun 04 10:42:50 2026
Version 19.27.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Master table "EXPOER"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "EXPOER"."SYS_IMPORT_TABLE_01":  expoer/********@hrpdb directory=IMP_DIR dumpfile=emp2_20260604.dmp tables=hr.emp2 TABLE_EXISTS_ACTION=TRUNCATE logfile=impdp_emp2_202606043.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Table "HR"."EMP2" exists and has been truncated. Data will be loaded but all dependent metadata will be skipped due to table_exists_action of truncate
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "HR"."EMP2"                                 13.75 KB     107 rows
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
Job "EXPOER"."SYS_IMPORT_TABLE_01" successfully completed at Thu Jun 04 10:42:54 2026 elapsed 0 00:00:03

[oracle@19cdb01 ~]$

impdp执行成功。

【小结】在Oracle 19c中业务表修改字段通过expdp和impdp可以成功完成变更。在Oracle 10g中可能会因为字段发生变化impdp失败。对于业务表修改字段的变更在19c中虽然通过empdp和impdp可以实现，但是我们建议针对此类变更操作可以先通过CTAS创建表，然后修改字段，最后重名表。也可以按目标要求创建好表在进行表级的数据迁移。

当我们在生产环境中频繁面对表结构变更和数据迁移时，仅仅依赖 TABLE_EXISTS_ACTION=TRUNCATE 虽然能成功，但在性能、安全和高可用上还有很大的优化空间。

如果是线下测试或小表变更，TABLE_EXISTS_ACTION=TRUNCATE 配合 PARALLEL 和 EXCLUDE=STATISTICS 是最快最省事的。但如果是生产环境核心大表，请优先考虑 DBMS_REDEFINITION 在线重定义，先建表后迁移数据（CONTENT=DATA_ONLY）的方案。

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