oracle历史命令

⑴ 关于oracle命令

alter table 表名 modify 字段名 not null;
不过你那个字段要是原来有空的，你执行会报错

⑵ oracle历史命令如何查看

windows 环境下用方向键上下来查看,

linux 下用rlwrap 包装

单纯查执行过的sql 可以查V$sql 和v$sqlarea

⑶ oracle 如何上翻回前一条命令

l (或L)
linux的话输入
sql>define_editor=vi
然后每次只需要输入ed就能进入vi编辑模式了。完成后只需要输入“/”就能重新执行编辑好的内容。
windows的话直接输入edit就能修改缓存区里的内容了。

⑷ 干货-Oracle里的常用命令

本文转自：51Testing软件测试网。（http://www.51testing.com/html/27/n-7827.html）

      第一章：日志管理

1.forcing log switches

sql> alter system switch logfile;

2.forcing checkpoints

sql> alter system checkpoint;

3.adding online redo log groups

sql> alter database add logfile [group 4]

sql> ('/disk3/log4a.rdo','/disk4/log4b.rdo') size 1m;

4.adding online redo log members

sql> alter database add logfile member

sql> '/disk3/log1b.rdo' to group 1,

sql> '/disk4/log2b.rdo' to group 2;

5.changes the name of the online redo logfile

sql> alter database rename file 'c:/oracle/oradata/oradb/redo01.log'

sql> to 'c:/oracle/oradata/redo01.log';

6.drop online redo log groups

sql> alter database drop logfile group 3;

7.drop online redo log members

sql> alter database drop logfile member 'c:/oracle/oradata/redo01.log';

8.clearing online redo log files

sql> alter database clear [unarchived] logfile 'c:/oracle/log2a.rdo';

9.using logminer analyzing redo logfiles

a. in the init.ora specify utl_file_dir = ' '

b. sql> execute dbms_logmnr_d.build('oradb.ora','c:\oracle\oradb\log');

c. sql> execute dbms_logmnr_add_logfile('c:\oracle\oradata\oradb\redo01.log',

sql> dbms_logmnr.new);

d. sql> execute dbms_logmnr.add_logfile('c:\oracle\oradata\oradb\redo02.log',

sql> dbms_logmnr.addfile);

e. sql> execute dbms_logmnr.start_logmnr(dictfilename=>'c:\oracle\oradb\log\oradb.ora');

f. sql> select * from v$logmnr_contents(v$logmnr_dictionary,v$logmnr_parameters

sql> v$logmnr_logs);

g. sql> execute dbms_logmnr.end_logmnr;

第二章：表空间管理

1.create tablespaces

sql> create tablespace tablespace_name datafile 'c:\oracle\oradata\file1.dbf' size 100m,

sql> 'c:\oracle\oradata\file2.dbf' size 100m minimum extent 550k [logging/nologging]

sql> default storage (initial 500k next 500k maxextents 500 pctinccease 0)

sql> [online/offline] [permanent/temporary] [extent_management_clause]

2.locally managed tablespace

sql> create tablespace user_data datafile 'c:\oracle\oradata\user_data01.dbf'

sql> size 500m extent management local uniform size 10m;

3.temporary tablespace

sql> create temporary tablespace temp tempfile 'c:\oracle\oradata\temp01.dbf'

sql> size 500m extent management local uniform size 10m;

4.change the storage setting

sql> alter tablespace app_data minimum extent 2m;

sql> alter tablespace app_data default storage(initial 2m next 2m maxextents 999);

5.taking tablespace offline or online

sql> alter tablespace app_data offline;

sql> alter tablespace app_data online;

6.read_only tablespace

sql> alter tablespace app_data read only|write;

7.droping tablespace

sql> drop tablespace app_data including contents;

8.enableing automatic extension of data files

sql> alter tablespace app_data add datafile 'c:\oracle\oradata\app_data01.dbf' size 200m

sql> autoextend on next 10m maxsize 500m;

9.change the size fo data files manually

sql> alter database datafile 'c:\oracle\oradata\app_data.dbf' resize 200m;

10.Moving data files: alter tablespace

sql> alter tablespace app_data rename datafile 'c:\oracle\oradata\app_data.dbf'

sql> to 'c:\oracle\app_data.dbf';

11.moving data files:alter database

sql> alter database rename file 'c:\oracle\oradata\app_data.dbf'

sql> to 'c:\oracle\app_data.dbf';

第三章：表

1.create a table

sql> create table table_name (column datatype,column datatype]....)

sql> tablespace tablespace_name [pctfree integer] [pctused integer]

sql> [initrans integer] [maxtrans integer]

sql> storage(initial 200k next 200k pctincrease 0 maxextents 50)

sql> [logging|nologging] [cache|nocache]

2. an existing table

sql> create table table_name [logging|nologging] as subquery

3.create temporary table

sql> create global temporary table xay_temp as select * from xay;

on commit preserve rows/on commit delete rows

4.pctfree = (average row size - initial row size) *100 /average row size

pctused = 100-pctfree- (average row size*100/available data space)

5.change storage and block utilization parameter

sql> alter table table_name pctfree=30 pctused=50 storage(next 500k

sql> minextents 2 maxextents 100);

6.manually allocating extents

sql> alter table table_name allocate extent(size 500k datafile 'c:/oracle/data.dbf');

7.move tablespace

sql> alter table employee move tablespace users;

8.deallocate of unused space

sql> alter table table_name deallocate unused [keep integer]

9.truncate a table

sql> truncate table table_name;

10.drop a table

sql> drop table table_name [cascade constraints];

11.drop a column

sql> alter table table_name drop column comments cascade constraints checkpoint 1000;

alter table table_name drop columns continue;

12.mark a column as unused

sql> alter table table_name set unused column comments cascade constraints;

alter table table_name drop unused columns checkpoint 1000;

alter table orders drop columns continue checkpoint 1000

data_dictionary : dba_unused_col_tabs

第四章：索引

1.creating function-based indexes

sql> create index summit.item_quantity on summit.item(quantity-quantity_shipped);

2.create a B-tree index

sql> create [unique] index index_name on table_name(column,.. asc/desc) tablespace

sql> tablespace_name [pctfree integer] [initrans integer] [maxtrans integer]

sql> [logging | nologging] [nosort] storage(initial 200k next 200k pctincrease 0

sql> maxextents 50);

3.pctfree(index)=(maximum number of rows-initial number of rows)*

100/maximum number of rows

4.creating reverse key indexes

sql> create unique index xay_id on xay(a) reverse pctfree 30 storage(initial 200k

sql> next 200k pctincrease 0 maxextents 50) tablespace indx;

5.create bitmap index

sql> create bitmap index xay_id on xay(a) pctfree 30 storage( initial 200k next 200k

sql> pctincrease 0 maxextents 50) tablespace indx;

6.change storage parameter of index

sql> alter index xay_id storage (next 400k maxextents 100);

7.allocating index space

sql> alter index xay_id allocate extent(size 200k datafile 'c:/oracle/index.dbf');

8.alter index xay_id deallocate unused;

第五章：约束

1.define constraints as immediate or deferred

sql> alter session set constraint[s] = immediate/deferred/default;

set constraint[s] constraint_name/all immediate/deferred;

2. sql> drop table table_name cascade constraints

sql> drop tablespace tablespace_name including contents cascade constraints

3. define constraints while create a table

sql> create table xay(id number(7) constraint xay_id primary key deferrable

sql> using index storage(initial 100k next 100k) tablespace indx);

primary key/unique/references table(column)/check

4.enable constraints

sql> alter table xay enable novalidate constraint xay_id;

5.enable constraints

sql> alter table xay enable validate constraint xay_id;

第六章：LOAD数据

1.loading data using direct_load insert

sql> insert /*+append */ into emp nologging

sql> select * from emp_old;

2.parallel direct-load insert

sql> alter session enable parallel dml;

sql> insert /*+parallel(emp,2) */ into emp nologging

sql> select * from emp_old;

3.using sql*loader

sql> sqlldr scott/tiger \

sql> control = ulcase6.ctl \

sql> log = ulcase6.log direct=true

第七章：reorganizing data

1.using expoty

$exp scott/tiger tables(dept,emp) file=c:\emp.dmp log=exp.log compress=n direct=y

2.using import

$imp scott/tiger tables(dept,emp) file=emp.dmp log=imp.log ignore=y

3.transporting a tablespace

sql>alter tablespace sales_ts read only;

$exp sys/.. file=xay.dmp transport_tablespace=y tablespace=sales_ts

triggers=n constraints=n

$ datafile

$imp sys/.. file=xay.dmp transport_tablespace=y datafiles=(/disk1/sles01.dbf,/disk2

/sles02.dbf)

sql> alter tablespace sales_ts read write;

4.checking transport set

sql> DBMS_tts.transport_set_check(ts_list =>'sales_ts' ..,incl_constraints=>true);

在表transport_set_violations 中查看

sql> dbms_tts.isselfcontained 为true 是， 表示自包含

第八章：managing password security and resources

1.controlling account lock and password

sql> alter user juncky identified by oracle account unlock;

2.user_provided password function

sql> function_name(userid in varchar2(30),password in varchar2(30),

old_password in varchar2(30)) return boolean

3.create a profile : password setting

sql> create profile grace_5 limit failed_login_attempts 3

sql> password_lock_time unlimited password_life_time 30

sql>password_reuse_time 30 password_verify_function verify_function

sql> password_grace_time 5;

4.altering a profile

sql> alter profile default failed_login_attempts 3

sql> password_life_time 60 password_grace_time 10;

5.drop a profile

sql> drop profile grace_5 [cascade];

6.create a profile : resource limit

sql> create profile developer_prof limit sessions_per_user 2

sql> cpu_per_session 10000 idle_time 60 connect_time 480;

7. view => resource_cost : alter resource cost

dba_Users,dba_profiles

8. enable resource limits

sql> alter system set resource_limit=true;

第九章：Managing users

1.create a user: database authentication

sql> create user juncky identified by oracle default tablespace users

sql> temporary tablespace temp quota 10m on data password expire

sql> [account lock|unlock] [profile profilename|default];

2.change user quota on tablespace

sql> alter user juncky quota 0 on users;

3.drop a user

sql> drop user juncky [cascade];

4. monitor user

view: dba_users , dba_ts_quotas

第十章：managing privileges

1.system privileges: view => system_privilege_map ,dba_sys_privs,session_privs

2.grant system privilege

sql> grant create session,create table to managers;

sql> grant create session to scott with admin option;

with admin option can grant or revoke privilege from any user or role;

3.sysdba and sysoper privileges:

sysoper: startup,shutdown,alter database open|mount,alter database backup controlfile,

alter tablespace begin/end backup,recover database

alter database archivelog,restricted session

sysdba: sysoper privileges with admin option,create database,recover database until

4.password file members: view:=> v$pwfile_users

5.O7_dictionary_accessibility =true restriction access to view or tables in other schema

6.revoke system privilege

sql> revoke create table from karen;

sql> revoke create session from scott;

7.grant object privilege

sql> grant execute on dbms_pipe to public;

sql> grant update(first_name,salary) on employee to karen with grant option;

8.display object privilege : view => dba_tab_privs, dba_col_privs

9.revoke object privilege

sql> revoke execute on dbms_pipe from scott [cascade constraints];

10.audit record view :=> sys.aud$

11. protecting the audit trail

sql> audit delete on sys.aud$ by access;

12.statement auditing

sql> audit user;

13.privilege auditing

sql> audit select any table by summit by access;

14.schema object auditing

sql> audit lock on summit.employee by access whenever successful;

15.view audit option : view=> all_def_audit_opts,dba_stmt_audit_opts,

dba_priv_audit_opts,dba_obj_audit_opts

16.view audit result: view=> dba_audit_trail,dba_audit_exists,dba_audit_object,

dba_audit_session,dba_audit_statement

第十一章： manager role

1.create roles

sql> create role sales_clerk;

sql> create role hr_clerk identified by bonus;

sql> create role hr_manager identified externally;

2.modify role

sql> alter role sales_clerk identified by commission;

sql> alter role hr_clerk identified externally;

sql> alter role hr_manager not identified;

3.assigning roles

sql> grant sales_clerk to scott;

sql> grant hr_clerk to hr_manager;

sql> grant hr_manager to scott with admin option;

4.establish default role

sql> alter user scott default role hr_clerk,sales_clerk;

sql> alter user scott default role all;

sql> alter user scott default role all except hr_clerk;

sql> alter user scott default role none;

5.enable and disable roles

sql> set role hr_clerk;

sql> set role sales_clerk identified by commission;

sql> set role all except sales_clerk;

sql> set role none;

6.remove role from user

sql> revoke sales_clerk from scott;

sql> revoke hr_manager from public;

7.remove role

sql> drop role hr_manager;

8.display role information

view: =>dba_roles,dba_role_privs,role_role_privs,dba_sys_privs,

role_sys_privs,role_tab_privs,session_roles

第十二章: BACKUP and RECOVERY

1. v$sga,v$instance,v$process,v$bgprocess,v$database,v$datafile,v$sgastat

2. Rman need set dbwr_IO_slaves or backup_tape_IO_slaves and large_pool_size

3. Monitoring Parallel Rollback

> v$fast_start_servers , v$fast_start_transactions

4.perform a closed database backup (noarchivelog)

> shutdown immediate

> cp files /backup/

> startup

5.restore to a different location

> connect system/manager as sysdba

> startup mount

> alter database rename file '/disk1/../user.dbf' to '/disk2/../user.dbf';

> alter database open;

6.recover syntax

--recover a mounted database

>recover database;

>recover datafile '/disk1/data/df2.dbf';

>alter database recover database;

--recover an opened database

>recover tablespace user_data;

>recover datafile 2;

>alter database recover datafile 2;

7.how to apply redo log files automatically

>set autorecovery on

>recover automatic datafile 4;

8.complete recovery:

--method 1(mounted databae)

> c:\backup\user.dbf c:\oradata\user.dbf

>startup mount

>recover datafile 'c:\oradata\user.dbf;

>alter database open;

--method 2(opened database,initially opened,not system or rollback datafile)

> c:\backup\user.dbf c:\oradata\user.dbf (alter tablespace offline)

>recover datafile 'c:\oradata\user.dbf' or

>recover tablespace user_data;

>alter database datafile 'c:\oradata\user.dbf' online or

>alter tablespace user_data online;

--method 3(opened database,initially closed not system or rollback datafile)

>startup mount

>alter database datafile 'c:\oradata\user.dbf' offline;

>alter database open

> c:\backup\user.dbf d:\oradata\user.dbf

>alter database rename file 'c:\oradata\user.dbf' to 'd:\oradata\user.dbf'

>recover datafile 'e:\oradata\user.dbf' or recover tablespace user_data;

>alter tablespace user_data online;

--method 4(loss of data file with no backup and have all archive log)

>alter tablespace user_data offline immediate;

>alter database create datafile 'd:\oradata\user.dbf' as 'c:\oradata\user.dbf''

>recover tablespace user_data;

>alter tablespace user_data online

5.perform an open database backup

> alter tablespace user_data begin backup;

> files /backup/

> alter database datafile '/c:/../data.dbf' end backup;

> alter system switch logfile;

6.backup a control file

> alter database backup controlfile to 'control1.bkp';

> alter database backup controlfile to trace;

7.recovery (noarchivelog mode)

> shutdown abort

> cp files

> startup

8.recovery of file in backup mode

>alter database datafile 2 end backup;

9.clearing redo log file

>alter database clear unarchived logfile group 1;

>alter database clear unarchived logfile group 1 unrecoverable datafile;

10.redo log recovery

>alter database add logfile group 3 'c:\oradata\redo03.log' size 1000k;

>alter database drop logfile group 1;

>alter database open;

or >cp c:\oradata\redo02.log' c:\oradata\redo01.log

>alter database clear logfile 'c:\oradata\log01.log';

⑸ oracle如何将表的历史数据归档

归档日志(ArchiveLog)是非活动的重做日志备份.通过使用归档日志,可以保留所有重做历史记录,当数据库处于ARCHIVELOG模式并进行日志切换式,后台进程ARCH会将重做日志的内容保存到归档日志中.当数据库出现介质失败时,使用数据文件备份,归档日志和重做日志可以完全恢复数据库.
日志操作模式:ARCHIVELOGNOARCHIVELOG
1,改变日志操作模式:
检查当前日志操作模式
SELECTlog_modefromv$database;
关闭数据库,然后装载数据库
SHUTDOWNIMMEDIATE
STARTUPMOUNT
改变日志操作模式,然后打开数据库
ALTERDATABASEARCHIVELOG;
ALTERDATABASEOPEN;
2,执行手工归档
从oracledatabase10g开始,当将日志操作模式转变未ARCHIVELOG模式时,oracle会自动启动ARCH进程.如果要使用手工归档.那么在改变日志操作模式时必须使用命令ALTERDATABASEARCHIVELOGMANUAL.
需要注意,使用手工归档方式,数据库管理员必须手工执行归档命令.如果没有执行手工归档命令,日志组的原有内容将不能被覆盖.ALTERDATABASEARCHIVELOGMANUAL命令是为了与先前的版本兼容而保留的,.将来的oracle版本会淘汰该命令,使用手工归档方式是,数据库管理员可以执行以下命令归档重做日志:
SLTERSYSTEMARCHIVELOGALL;
3,配置归档进程
初始化参数LOG_ARCHIVE_MAX_PROCESSES用于指定例程初始启动的最大归档进程个数,当将数据库转变为ARCHIVELOG模式时,默认情况下oracle会自动启动两个归档进程.通过改变初始化参数LOG_ARCHIVE_MAX_PROCESS的值,可以动态地增加或降低归档进程的个数:
ALTERSYSTEMSETLOG_ARCHIVE_MAX_PROCESSES=3;

配置归档位置和文件格式
当数据库处于ARCHIVELOG模式时,如果进行日志切换,后台进程将自动生成归档日志,归档日志的默认位置为%oracle_home%rdbms,在oracledatabase10g中,归档日志的默认文件格式为ARC%S_%R.%T.为了改变归档日志的位置和名称格式,必须改变相应的初始化参数,
1,初始化参数LOG_ARCHIVE_FORMAT用于指定归档日志的文件名格式,设置该初始化参数时,可以指定以下匹配符:
%s:日志序列号:
%S:日志序列号(带有前导0)
%t:重做线程编号.
%T:重做线程编号(带有前导0)
%a:活动ID号
%d:数据库ID号
%rRESETLOGS的ID值.
从10g开始,配置归档日志文件格式时,必须带有%s,%t和%r匹配符,配置了归档文件格式后,必须重启数据库.
2,使用LOG_ARCHIVE_DEST配置归档位置
如果不使用备用数据库,只需要将归档日志存放到本地目录.配置本地归档位置可以使用初始化参数LOG_ARCHIVE_DEST和LOG_ARCHIVE_DUPLEX_DEST,其中,第一个参数用于设置第一个归档位置,第二个参数用于指定第二个归档位置.
ALTERSYSTEMSETlog_archive_dest=’d:demoarchive1’;
ALTERSYSTEMSETlog_archive_plex_dest=’d:demoarchive2’;
3,使用LOG_ARCHIVE_DEST_n配置多个归档位置.
初始化参数LOG_ARCHIVE_DEST_n用于指定多个归档位置,该参数最多可以指定10个归档位置.通过使用初始化参数LOG_ARCHIVE_DEST_n,不仅可以配置本地归档位置,还可以配置远程归档位置.
如果既要在主节点上生成归档日志,又要将归档日志传递到备用节点,那么必须使用参数LOG_ARCHIVE_DEST_n.该参数与LOG_ARCHIVE_DEST具有如下区别;
初始化参数LOG_ARCHIVE_DEST_n可以配置本地归档位置和远程归档位置,而初始化参数LOG_ARCHIVE_DEST和LOG_ARCHIVE_DUPLEX_DEST只能配置本地归档位置.
初始化参数LOG_ARCHIVE_DEST_n可以配置多达10个归档位置,而初始化参数LOG_ARCHIVE_DEST和LOG_ARCHIVE_DUPLEX_DEST最多只能配置两个归档位置.
初始化参数LOG_ARCHIVE_DEST_n不能与初始化参数LOG_ARCHIVE_DEST和LOG_ARCHIVE_DUPLEX_DEST同时使用.
因为初始化参数LOG_ARCHIVE_DEST_n不能与初始化参数LOG_ARCHIVE_DEST和LOG_ARCHIVE_DUPLEX_DEST同时使用,所以必须禁用初始化参数LOG_ARCHVE_DEST和LOG_ARCHIVE_DUPLEX_DEST.当使用初始化参数LOG_ARCHIVE_DEST_n配置本地归档位置时,需要指定LOCALTION选项.当配置远程归档位置时,需要指定SERVICE选项.
示例如下:
ALTERSYSTEMSETlog_archive_plex_dest=’’;
ALTERSYSTEMSETlog_archive_dest=’’;
ALTERSYSTEMSETlog_archive_dest_1=’location=d:demoarchive1’;
ALTERSYSTEMSETlog_archive_dest_2=’location=d:demoarchive2’;
ALTERSYSTEMSETlog_archive_dest_3=’location=d:demoarchive3’;
ALTERSYSTEMSETlog_archive_dest_4=’service=standby’;
配置远程归档位置时,SERVICE选项需要指定远程数据库的网络服务名(在tnsnames.ora文件中配置)
4,使用LOG_ARCHIVE_DEST_n选项
使用初始化参数LOG_ARCHIVE_DEST_n配置归档位置时,可以在归档位置上指定OPTIONAL或MANDATORY选项.指定MANDATORY选项时,可以设置REOPEN属性.
OPTIONAL:该选项是默认选项.使用该选项时,无论归档是否成功,都可以覆盖重做日志.
MANDATORY:强制归档.使用该选项时,只有在归档成功之后,重做日志才能被覆盖.
REOPEN:该属性用于指定重新归档的时间间隔,默认值为300秒,必须跟在MANDATORY后.
例:
Altersystemsetlog_archive_dest_1=’location=d:demoarchive1mandatory’;
Altersystemsetlog_archive_dest_2=’location=d:demoarchive2mandatoryreopen=500’;
Altersystemsetlog_archive_dest_3=’location=d:demoarchive3optional’;
5,控制本地归档成功的最小个数.
使用初始化参数LOG_ARCHIVE_MIN_SUCCEED_DEST控制本地归档的最小成功个数
Altersystemsetlog_archive_min_succeed_dest=2;
6,使用初始化参数LOG_ARCHIVE_DEST_STATE_n控制归档位置的可用性.设置该参数为ENABLE(默认值),表示会激活相应的归档位置;设置该参数为DEFER,表示禁用相应归档位置.当归档日志所在磁盘损坏或填满时,DBA需要暂时禁用该归档位置.
Altersystemsetlog_archive_dest_state_3=defer;(禁用)
Altersystemsetlog_archive_dest_state_3=enable;(启用)

显示归档日志信息
1,使用ARCHIVELOGLIST命令可以显示日志操作模式,归档位置,自动归档机器要归档的日志序列号等信息.
2显示日志操作模式
SELECTname,log_modeFROMv$database;
3,显示归档日志信息.
Colnameformata40
Selectname,swquence#,first_change#FROMv$archived_log;
Name用于表示归档日志文件名,sequence#用于表示归档日志对应的日志序列号,firs_change#用于标识归档日志的起始SCN值.
4执行介质恢复时,需要使用归档日志文件,此四必须准确定位归档日志的存放位置.通过查询动态性能视图v$archive_dest可以取得归档日志所在目录.
SELECTdestinationFROMv$archivedest;
5,显示日志历史信息
SELECT*FROMv$loghist;
THREAD#用于标识重做线程号,SEQUNCE#用于标识日志序列号,FIRST_CHANGE#用于标识日志序列号对应的起始SCN值,FIRST_TIME用于标识起始SCN的发生时间.SWICTH_CHANGE#用于标识日志切换的SCN值.
6.显示归档进程信息.
进行日志切换时,ARCH进程会自动将重做日志内容复制到归档日志中,为了加快归档速度,应该启用多个ARCH进程.通过查询动态性能视图V$ARCHIVE_PROCESSES可以显示所有归档进程的信息!
SELECT*FROMv$archive_processes;
Porcess用于标识ARCH进程的编号,status用于标识ARCH进程的状态(ACTIVE:活动,STOPPED:未启动),log_sequence用于标识正在进行归档的日志序列号,state用于标识ARCH进程的工作状态

⑹ win7下开启ORACLE服务命令

操作方法如下：

1、按win+r，输入net start OracleServiceORCL，点击确定；

⑺ oracle命令

select * from a where b>10000;

⑻ Oracle 命令

再有值的情况下不能直接修改字段属性
但是可以通过其他办法得到
举个例子
1.先增加一个字段 alter table table_name add fieldname_C int;
2.更新改字段为你要的
update table_name set fieldname_C=to_number(fieldname_A)+50 where 日期条件;
commit;
3.删除A字段
alter table table_name drop column ....
4.更新C字段名字为A字段
alter table table_name rename column C to A;

⑼ oracle基本命令

1.用户有哪些表空间概念错了,只能看用户用了哪些user_tablespaces视图就可以
select tablespace_name from dba_tablespaces;
2.变量填自己的
select owner,table_name from dba_tables where tablespace_name='SYSTEM';
select tablespace_name from dba_tables where table_name='EMP';