适用范围

--源端
SQL>desc emp1
 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)
SQL>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)>
                                           VARCHAR2(30)
--目标端
SQL>desc emp1
 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 
SQL>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

经过比对，expdp的源端HR用户下的emp1和emp2表结构与impdp的目标环境不一致。

小结：impdp时使用 TABLE_EXISTS_ACTION=TRUNCATE 或 APPEND 且仅导入数据时，Data Pump 内部代码需要比对元数据以确保字段能正确映射。此比对过程在内部会调用元数据 XML 解析引擎。如果两端结构不匹配，内部 XML 解析逻辑会触发 ORA-38500 错误。

建议：在11g版本中进行impdp时业务用户表结构源与目标端应该保持一致，防止应字段不一致导致作业失败以及影响业务。

-the end-

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