修改数据库字符集

本文介绍如何在Oracle数据库中更改字符集。通过一系列SQL命令演示了从AL32UTF8到ZHS16GBK的转换过程,并解释了在不同操作模式下进行字符集转换的要求。

数据库导入导出的时候经常会提示字符集不同,可以通过下面方法修改数据库字符集:


SQL> alter database character set ZHS16GBK;
alter database character set ZHS16GBK
*
ERROR at line 1:
ORA-12712: new character set must be a superset of old character set


SQL> ALTER DATABASE character set INTERNAL_USE zhs16gbk;
ALTER DATABASE character set INTERNAL_USE zhs16gbk
*
ERROR at line 1:
ORA-12719: operation requires database is in RESTRICTED mode


SQL> select value from nls_database_parameters where parameter='NLS_CHARACTERSE
';

VALUE
-------------------------------------------------------------------------------

AL32UTF8

SQL> conn sys/system as sysdba
Connected.
SQL> startup
ORA-01081: cannot start already-running ORACLE - shut it down first
SQL> select name,value$ from props$ where name like '%NLS%';

NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_LANGUAGE
AMERICAN

NLS_TERRITORY
AMERICA

NLS_CURRENCY
$


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_ISO_CURRENCY
AMERICA

NLS_NUMERIC_CHARACTERS
.,

NLS_CHARACTERSET
AL32UTF8


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_CALENDAR
GREGORIAN

NLS_DATE_FORMAT
DD-MON-RR

NLS_DATE_LANGUAGE
AMERICAN


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_SORT
BINARY

NLS_TIME_FORMAT
HH.MI.SSXFF AM

NLS_TIMESTAMP_FORMAT
DD-MON-RR HH.MI.SSXFF AM


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_TIME_TZ_FORMAT
HH.MI.SSXFF AM TZR

NLS_TIMESTAMP_TZ_FORMAT
DD-MON-RR HH.MI.SSXFF AM TZR

NLS_DUAL_CURRENCY
$


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_COMP
BINARY

NLS_LENGTH_SEMANTICS
BYTE

NLS_NCHAR_CONV_EXCP
FALSE


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------

NLS_NCHAR_CHARACTERSET
AL16UTF16

NLS_RDBMS_VERSION
10.2.0.4.0


20 rows selected.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 1610612736 bytes
Fixed Size                  2066080 bytes
Variable Size             385878368 bytes
Database Buffers         1207959552 bytes
Redo Buffers               14708736 bytes
Database mounted.
SQL> alter session set sql_trace=true;

Session altered.

SQL> alter system enable restricted session;

System altered.

SQL> alter system set job_queue_processes=0;

System altered.

SQL> alter system set aq_tm_processes=0;

System altered.

SQL> alter database open;

Database altered.

SQL> set linesize 120;
SQL>  alter database character set zhs16gbk;
 alter database character set zhs16gbk
*
ERROR at line 1:
ORA-12712: new character set must be a superset of old character set


SQL> ALTER DATABASE character set INTERNAL_USE zhs16gbk;

Database altered.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> shutdown immediate;
ORA-01012: not logged on
SQL> STARTUP
ORACLE instance started.

Total System Global Area 1610612736 bytes
Fixed Size                  2066080 bytes
Variable Size             385878368 bytes
Database Buffers         1207959552 bytes
Redo Buffers               14708736 bytes
Database mounted.
Database opened.
SQL> select name,value$ from props$ where name like '%NLS%';

NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_LANGUAGE
AMERICAN

NLS_TERRITORY
AMERICA

NLS_CURRENCY
$


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_ISO_CURRENCY
AMERICA

NLS_NUMERIC_CHARACTERS
.,

NLS_CHARACTERSET
ZHS16GBK


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_CALENDAR
GREGORIAN

NLS_DATE_FORMAT
DD-MON-RR

NLS_DATE_LANGUAGE
AMERICAN


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_SORT
BINARY

NLS_TIME_FORMAT
HH.MI.SSXFF AM

NLS_TIMESTAMP_FORMAT
DD-MON-RR HH.MI.SSXFF AM


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_TIME_TZ_FORMAT
HH.MI.SSXFF AM TZR

NLS_TIMESTAMP_TZ_FORMAT
DD-MON-RR HH.MI.SSXFF AM TZR

NLS_DUAL_CURRENCY
$


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_COMP
BINARY

NLS_LENGTH_SEMANTICS
BYTE

NLS_NCHAR_CONV_EXCP
FALSE


NAME
------------------------------
VALUE$
-------------------------------------------------------------------------------
----------------------------------------
NLS_NCHAR_CHARACTERSET
AL16UTF16

NLS_RDBMS_VERSION
10.2.0.4.0


20 rows selected.

SQL>



### 修改 Oracle 数据库字符集的详细步骤 修改 Oracle 数据库字符集是一项高风险操作,通常不建议在已创建的数据库中进行。如果确实需要修改字符集,可以使用以下方法: #### 1. 查询当前字符集修改字符集之前,首先需要确认当前数据库字符集。可以通过以下 SQL 查询当前字符集: ```sql SELECT VALUE$ FROM SYS.props$ WHERE NAME$ = 'NLS_CHARACTERSET'; ``` #### 2. 关闭数据库 以 `sysdba` 身份登录到 Oracle 数据库,并关闭数据库: ```sql SQL> conn / as sysdba; SQL> SHUTDOWN IMMEDIATE; ``` #### 3. 启动数据库到 Mount 状态 启动数据库到 `MOUNT` 状态: ```sql SQL> STARTUP MOUNT; ``` #### 4. 启用受限会话模式 启用受限会话模式,以确保只有管理员可以访问数据库: ```sql SQL> ALTER SYSTEM ENABLE RESTRICTED SESSION; ``` #### 5. 设置并发执行作业时使用的进程数量为 0 设置并发执行作业时使用的进程数量为 0: ```sql SQL> ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0; ``` #### 6. 打开数据库 打开数据库: ```sql SQL> ALTER DATABASE OPEN; ``` #### 7. 修改数据库字符集 使用 `ALTER DATABASE CHARACTER SET` 命令修改字符集。例如,将字符集修改为 `ZHS16GBK`: ```sql SQL> ALTER DATABASE CHARACTER SET ZHS16GBK; ``` #### 8. 修改国家字符集 修改国家字符集: ```sql SQL> ALTER DATABASE NATIONAL CHARACTER SET ZHS16GBK; ``` #### 9. 关闭并重新启动数据库 关闭数据库并重新启动: ```sql SQL> SHUTDOWN IMMEDIATE; SQL> STARTUP; ``` ### 注意事项 - **备份数据库**:在执行这些步骤之前,请务必备份数据库,并在生产环境之外的测试环境中进行测试。 - **字符集限制**:修改数据库字符集时,只有新的字符集是当前字符集的超集时才能修改数据库字符集。如果两种字符集之间没有子集和超集的关系,字符集的转换是不受 Oracle 支持的[^4]。 - **咨询专业人士**:建议在此过程中咨询 Oracle 官方文档或专业的 Oracle 数据库管理员以获取准确的指导和支持[^3]。 ###
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值