Oracle修改字符集前怎么找出可能出现问题的数据

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场景1：

将A库数据迁移到B库，其中A库字符集ZHS16GBK，B库字符集AL32UTF8；

场景2：

修改A库字符集，由ZHS16GBK改成AL32UTF8。

问题：

如何提前知道在以上两个场景下，哪些数据会出现问题，例如字段长度溢出等问题？

解决方案：

Oracle有自带的Character Set Scanner(CSSCAN)工具,可以提前收集转换字符集出现错误的数据。

如下：

Oracle使用CSSCAN工具，检查某用户或表字符集转换后是否有错误

一：执行csminst.sql脚本

SQL> @?/rdbms/admin/csminst.sql

二：csscan使用语法：

[oracle@cjcos01 ~]$ csscan -helpCharacter Set Scanner v2.2 : Release 11.2.0.4.0 - Production on Wed Jun 17 13:46:29 2020Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.You can let Scanner prompt you for parameters by entering the CSSCAN        command followed by your username/password:                                                                                                               Example: CSSCAN \"SYSTEM/MANAGER AS SYSDBA\"                                                                                                      Or, you can control how Scanner runs by entering the CSSCAN command         followed by various parameters. To specify parameters, you use keywords:                                                                                  Example:                                                                      CSSCAN \"SYSTEM/MANAGER AS SYSDBA\" FULL=y TOCHAR=utf8 ARRAY=1024000 PROCESS=3                                                                              Keyword    Default Prompt Description                                       ---------- ------- ------ ------------------------------------------------- USERID             yes    username/password                                 FULL       N       yes    scan entire database                              USER               yes    owner of tables to be scanned                     TABLE              yes    list of tables to scan                            COLUMN             yes    list of columns to scan                            EXCLUDE                   list of tables to exclude from scan               TOCHAR             yes    new database character set name                   FROMCHAR                  current database character set name               TONCHAR                   new national character set name                   FROMNCHAR                 current national character set name               ARRAY      1024000 yes    size of array fetch buffer                        PROCESS    1       yes    number of concurrent scan process                 MAXBLOCKS                 split table if block size exceed MAXBLOCKS        CAPTURE    N              capture convertible data                          SUPPRESS                  maximum number of exceptions logged for each tableFEEDBACK                  report progress every N rows                      BOUNDARIES                list of column size boundaries for summary report LASTRPT    N              generate report of the last database scan         LOG        scan           base file name of report files                    PARFILE                   parameter file name                               PRESERVE   N              preserve existing scan results                    LCSD       N       no     enable language and character set detection       LCSDDATA   LOSSY   no     define the scope of the detection                 HELP       N              show help screen (this screen)                    QUERY      N              select clause to scan subset of tables or columns ---------- ------- ------ ------------------------------------------------- Scanner terminated successfully.

三：使用csscan工具，生成scan.err等信息

[oracle@cjcos01 ~]$ csscan Character Set Scanner v2.2 : Release 11.2.0.4.0 - Production on Wed Jun 17 11:47:21 2020Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.Username: sys as sysdbaPassword: Connected to:Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit ProductionWith the Partitioning, OLAP, Data Mining and Real Application Testing options(1)Full database, (2)User, (3)Table, (4)Column: 1 > 2Current database character set is ZHS16GBK.Enter new database character set name: > AL32UTF8Enter array fetch buffer size: 1024000 > Enter number of scan processes to utilize(1..): 1 > Enter user name to scan: > CJC......

四：检查转换字符集后哪些表出现错误，单独处理

[oracle@cjcos01 ~]$ ls

scan.err scan.out scan.txt

五：修改数据库字符集

首先要确定修改后的字符集应该是修改前的超集。

修改数据库字符集方式：

1：执行csalter.plb脚本

2：ALTER DATABASE CHARACTER ...

3: 修改prop$等表(此方法有风险，严禁使用)

参考：

Changing the NLS_CHARACTERSET to AL32UTF8 / UTF8 (Unicode) in 8i, 9i , 10g and 11g (文档 ID 260192.1)

Oracle 单机修改数据库字符集

10.a.2) Execute the following commands in the database home sqlplus connected as "/ AS SYSDBA":Sqlplus / as sysdbaSPOOL Nswitch.logSHUTDOWN IMMEDIATE;STARTUP MOUNT;ALTER SYSTEM ENABLE RESTRICTED SESSION;ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;ALTER SYSTEM SET AQ_TM_PROCESSES=0;ALTER DATABASE OPEN;-- Do not do these steps on a 10g or 11g systemALTER DATABASE CHARACTER SET INTERNAL_USE AL32UTF8;SHUTDOWN IMMEDIATE;-- You NEED to restart the database before doing ANY operation on this database-- exit this session now do not use the session that did alter database for other operationsEXIT-- reconnect to the database and start the databaseSqlplus / as sysdbaSTARTUP;-- in 8i you need to do the startup/shutdown 2 timesSHUTDOWN;STARTUP;

Oracle RAC 修改数据库字符集

If you are using RAC you will need to start the database in single instance with CLUSTER_DATABASE = FALSERun in the database home sqlplus connected as "/ AS SYSDBA":Sqlplus / as sysdba-- Make sure the CLUSTER_DATABASE parameter is set-- to false or it is not set at all.-- If you are using RAC you will need to start the database in single instance-- with CLUSTER_DATABASE = FALSEsho parameter CLUSTER_DATABASE-- if you are using spfileSELECT DECODE(value, NULL, 'PFILE', 'SPFILE') "Init File Type" FROM sys.v_$parameter WHERE name = 'spfile';-- note the values forsho parameter job_queue_processessho parameter aq_tm_processes-- (this is Bug 6005344 fixed in 11g )-- then doshutdownstartup restrictSPOOL Nswitch.logPURGE DBA_RECYCLEBIN/-- next select should only give ONE row - your sqlplus connection-- If more then one session is connected Csalter will fail and report "Sorry only one session is allowed to run this script".SELECT sid, serial#, username, status,  osuser, machine, process, program FROM v$session WHERE username IS NOT NULL;-- do this alter system or you might run into "ORA-22839: Direct updates on SYS_NC columns are disallowed"-- This is only needed in 11.1.0.6, fixed in 11.1.0.7, not applicable to 10.2 or lower-- ALTER SYSTEM SET EVENTS '22838 TRACE NAME CONTEXT LEVEL 1,FOREVER';-- then run Csalter.plb: @?/rdbms/admin/csalter.plb-- Csalter will aks confirmation - do not copy paste the whole actions on one time-- sample Csalter output:-- 3 rows created....-- This script will update the content of the Oracle Data Dictionary.-- Please ensure you have a full backup before initiating this procedure.-- Would you like to proceed (Y/N)?y-- old 6: if (UPPER('&conf') <> 'Y') then-- New 6: if (UPPER('y') <> 'Y') then-- Checking data validility...-- begin converting system objects-- PL/SQL procedure successfully completed.-- Alter the database character set...-- CSALTER operation completed, please restart database-- PL/SQL procedure successfully completed....-- Procedure dropped.-- if you are using spfile then you need to also-- ALTER SYSTEM SET job_queue_processes= SCOPE=BOTH;-- ALTER SYSTEM SET aq_tm_processes= SCOPE=BOTH;SHUTDOWN IMMEDIATE;-- You NEED to restart the database before doing ANY operation on this database-- exit this session now. do not use the session where Csalter was runned for other operations.EXIT-- reconnect to the database and start the databaseSqlplus / as sysdbaSTARTUP;

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