imp导入数据到ORACLE遭遇ORA-12899错误

错误信息：

IMP-00019: row rejected due to ORACLE error12899
IMP-00003: ORACLE error 12899 encountered
ORA-12899: value too large for column"JRGAZX"."DTLMB"."CC" (actual: 66,maximum: 50)

初步断定是字符集问题，中文在UTF-8里占3个字节，ZHS16GBK里占2个字节,而源dmp文件字符集是ZHS16GBK的库到出来的，现在要导入到目标字符集为UFT-8的库里。

修改oracle 10g的字符集
Oracle
修改数据库字符集为：ZHS16GBK
查看服务器端字符集SQL > select * from V$NLS_PARAMETERS
修改：$sqlplus /nolog
SQL>conn / as sysdba

SQL>SHUTDOWN IMMEDIATE
SQL>STARTUP MOUNT
SQL>ALTER SYSTEM ENABLE RESTRICTED SESSION;
SQL>ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
SQL>ALTER SYSTEM SET AQ_TM_PROCESSES=0;
SQL>ALTER DATABASE OPEN;

SQL> ALTER DATABASE CHARACTER SET ZHS16GBK;
ALTER DATABASE CHARACTER SET ZHS16GBK
*ERROR at line 1:
ORA-12712: new character set must be a superset ofold character set

报字符集不兼容，此时下INTERNAL_USE指令不对字符集超集进行检查：

SQL>ALTER DATABASE CHARACTER SET INTERNAL_USEZHS16GBK;
SQL>SHUTDOWN IMMEDIATE
SQL>STARTUP

再次用imp导入，就没有问题了。

oracle@server$ imp jrgazx/jrgazxfile=/opt/jrgazx1/jrgazx1.dmp  fromuser=jrgazxTABLES=CWFXZB,CXQK,DQBGYYPLSJB,DQTZSM,DSYP,DTLMB

Import: Release 10.2.0.1.0 - Production on WedMay 27 01:22:54 2009
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to: Oracle Database 10g EnterpriseEdition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
Export file created by EXPORT:V10.02.01 viaconventional path
import done in US7ASCII character set and AL16UTF16 NCHAR characterset
import server uses ZHS16GBK character set (possible charsetconversion)
export client uses ZHS16GBK character set (possible charsetconversion)
. importing JRGAZX's objects into JRGAZX
. importing JRGAZX's objects into JRGAZX
. . importingtable                      "CWFXZB"      57197 rows imported
. . importingtable                        "CXQK"       8471 rows imported
. . importingtable                 "DQBGYYPLSJB"      30593 rowsimported
. . importingtable                      "DQTZSM"      11173 rows imported
. . importingtable                        "DSYP"       4906 rows imported
. . importingtable                       "DTLMB"     390372 rows imported
Import terminated successfully without warnings.

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