(1)查看字符集（三条都是等价的）
代码如下:select * from v$nls_parameters where parameter=’NLS_CHARACTERSET’
select * from nls_database_parameters where parameter=’NLS_CHARACTERSET’
select * from props$ where name=’NLS_CHARACTERSET’
(2)查看国家字符集（三条都是等价的）
代码如下:select * from nls_database_parameters where parameter=’NLS_NCHAR_CHARACTERSET’
select * from nls_database_parameters where parameter=’NLS_NCHAR_CHARACTERSET’
select * from props$ where name=’NLS_NCHAR_CHARACTERSET’
(3)查看oracle server端的字符集
代码如下:select userenv(‘language’) from dual
(4)DataFile操作
代码如下:–DataFile联机
ALTER TABLESPACE BSS11 ONLINE
ALTER DATABASE ‘BSS_03.dbf’ ONLINE

–DataFile脱机
ALTER TABLESPACE BSS11 OFFLINE –作用对象：表空间BSS11的所有datafile
ALTER DATABASE ‘BSS_03.dbf’ OFFLINE —作用对象：BSS_03.dbf，就一个datafile–resize datafile
ALTER DATABASE DATAFILE ‘BSS_03.dbf’ RESIZE 500M;