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http://blog.sina.com.cn/s/blog_406a1d3f0100qz2f.html
连接数据库
D:\>sqlplus /nolog --运行sqlplus命令，进入sqlplus环境，/nolog参数表示不登录
SQL>conn / as sysdba; 以dba身份连接(登录)数据库
或者
D:\>sqlplus user/password as sysdba;
创建用户
SQL>create user maiyo identified by password;
SQL>grant dba to maiyo; 为用户maiyo赋予dba权限
更改用户密码
SQL>alter user maiyo identified by password;
解锁用户
SQL>alter user hr account unlock; 解锁hr用户；
查看已创建用户
SQL>select username from dba_users(或all_users);
查看用户状态
SQL>select username,account_status from dba_users where username='HR';
查看用户表
SQL>select table_name from user_tables;
查看表结构
SQL> desc mytable;
创建表
SQL>create table mytable(emp_id number(10),name varchar2(20),age number(3));
更改表
SQL>alter table mytable add(psd number(10));添加列
SQL>alter table mytable drop column age;删除age列
SQL>drop table mytable;删除表
插入表数据
SQL>insert into mytable(emp_id,name,age) values(1,'maiyo',24);
更改表数据
SQL>update mytable set age = 25 where name = 'maiyo';
删除表数据
SQL>delete mytable where name = 'maiyo';