导入的时候总是出现警告
C:Documents and SettingsAaron>exp system/manager@prod tables=GL.GL_balanceS
query=" where period_name='2009-07'" file=D:/EXP/GL_balanceS.dmp grants=y
Export: Release 10.2.0.1.0 - Production on Mon Aug 10 17:12:16 2009
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit
Production
With the Partitioning, OLAP and Data Mining options
Export done in ZHS16GBK character set and AL16UTF16 NCHAR character set
About to export specified tables via Conventional Path ...
Current user changed to GL
. . exporting table GL_BALANCES 3710 rows exported
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
EXP-00091: Exporting questionable statistics.
Export terminated successfully with warnings.
exp apps/apps@prod tables=GL.GL_JE_BATCHES query="where actual_flag='A' and creation_date>=sysdate-5" file=D:/EXP/GL_JE_BATCHES.dmp grants=y
exp system/manager@prod tables=GL.GL_JE_BATCHES query="where actual_flag='A' and creation_date>=sysdate-5" file=D:/EXP/GL_JE_BATCHES.dmp grants=y
exp system/manager@prod tables=GL.GL_JE_headerS query="where actual_flag='A' and creation_date>=sysdate-5" file=D:/EXP/GL_JE_headerS.dmp grants=y
exp system/manager@prod tables=GL.GL_JE_LINES query=" where creation_date>=sysdate-5" file=D:/EXP/GL_JE_LINES.dmp grants=y
exp system/manager@prod tables=GL.GL_SETS_OF_BOOKS file=D:/EXP/GL_SETS_OF_BOOKS.dmp grants=y
exp system/manager@prod tables=GL.GL_PERIODS query="where period_name = '2009-07'" file=D:/EXP/GL_PERIODS.dmp grants=y
exp system/manager@prod tables=GL.GL_CODE_COMBINATIONS query=" where summary_flag='N'" file=D:/EXP/GL_CODE_COMBINATIONS.dmp grants=y
exp system/manager@prod tables=GL.GL_balanceS query=" where period_name='2009-07'" file=D:/EXP/GL_balanceS.dmp grants=y
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解決EXP-00091的方法
對一個DBA或需使用exp,imp的普通用戶來說，在我們做exp的過程中可能經常會遇到EXP－00091 Exporting questionable statistics.這樣的EXP信息，其實它就是exp的error message，它產生的原因是因為我們exp工具所在的環境變量中的NLS_LANG與DB中的NLS_CHARACTERSET不一致。但需說明的是，exp-91這個error message對所生成的dump檔沒有影響，生成的dump檔還可以正常的imp（個人體會，不知道有沒有
錯），雖然它對我們的dump檔沒有影響，我個人還是不想它出現，大家也有同感吧， 。。下面我們就讓它消失吧
step 01 查看DB中的NLS_CHARACTERSET的值（提供兩種方法）：
select * from nls_database_parameters t where
t.parameter='NLS_CHARACTERSET'
or
select * from v$nls_parameters where
parameter='NLS_CHARACTERSET';
SQL> select * from v$nls_parameters where
parameter='NLS_CHARACTERSET';
PARAMETER VALUE
----------------------- -------------------------
---------------------
NLS_CHARACTERSET ZHT16BIG5
step 02 根據step 01查出的NLS_CHARACTERSET（ZHT16BIG5）來設定
exp的環境變量：
WINNT> set NLS_LANG=AMERICAN_AMERICA.ZHT16BIG5
LINUX> export NLS_LANG=AMERICAN_AMERICA.ZHT16BIG5