oracle常用知识-红联Linux系统门户

数据备份命令

exp mll/mll full=y rows=y statistics=none file=070306.dmp

vi .bash_profile

# .bash_profile

Oracle中的字符编码一定要设成和系统一样的才行，否则后果很严重

# Get the aliases and functions

if [ -f ~/.bashrc ]; then

. ~/.bashrc

fi

# User specific environment and startup programs

PATH=$PATH:$HOME/bin

export PATH

unset USERNAME

export ORACLE_BASE=/u01/app/oracle

export ORACLE_HOME=$ORACLE_BASE/10.2.0/db_1

export ORACLE_SID=mailaili

export PATH=$PATH:$ORACLE_HOME/bin

export NLS_LANG="SIMPLIFIED CHINESE_CHINA.ZHS16GBK"

export NLS_DATE_FORMAT="DD-MON-YYYY HH24:MI:SS"

export nls_language='SIMPLIFIED CHINESE'

建数据库的时侯也得选择CHINESE_CHINA.ZHS16GBK的字符集，这样在开发的过程当中才不会出错。

设置linux中的语言环境，在/etc/profile中加入export LC_ALL=zh_CN.GBK

如果在设置归档日志中出错,执行这条语句

SQL>ALTER SYSTEM RESET log_archive_start SCOPE=SPFILE SID='*';

如果在exp中出现

?一?DBA或需使用exp,imp的普通用???，在我?做exp的?程中可能?常?遇到EXP－00091 Exporting questionable statistics.??的EXP信息，其?它就是exp的error message，它?生的原因是因?我?exp工具所在的?境?量中的NLS_LANG?DB中的NLS_CHARACTERSET不一致。但需?明的是，exp-91??error message?所生成的dump??有影?，生成的dump??可以正常的imp（?人??，不知道有?有?），?然它?我?的dump??有影?，我?人?是不想它出?，大家也有同感吧，　。。下面我?就?它消失吧。。我?一起?

step 01　查看DB中的NLS_CHARACTERSET的值（提供??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?step 01查出的NLS_CHARACTERSET（ZHT16BIG5）??定exp的?境?量：

WINNT> set NLS_LANG=AMERICAN_AMERICA.ZHT16BIG5
LINUX> export NLS_LANG=AMERICAN_AMERICA.ZHT16BIG5

附上exp-91的oracle error message 解?方案?明：

oerr exp 91
00091, 00000, "Exporting questionable statistics."
// *Cause: Export was able export statistics, but the statistics may not be
// usuable. The statistics are questionable because one or more of
// the following happened during export: a row error occurred, client
// character set or NCHARSET does not match with the server, a query
// clause was specified on export, only certain partitions or
// subpartitions were exported, or a fatal error occurred while
// processing a table.
// *Action: To export non-questionable statistics, change the client character
// set or NCHARSET to match the server, export with no query clause,
// export complete tables. If desired, import parameters can be
// supplied so that only non-questionable statistics will be imported,
// and all questionable statistics will be recalculated.

使用如下语句删除一个表中的记录
delete from test where field1='200409'
test表中有几千万条记录，上面的语句要删除的记录数也有几百万条，这样等待的时间非常漫长，请问如何能加快删除速度？上面的语句如何改才能实现快速删除记录？

oracle常用知识

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