create tablespace ybp_dev datafile ‘G:\app\Administrator\oradata\health\ybp_dev1.dbf‘ size 10m autoextend on;create user 用户名 default tablespace 表空间名 identified by 用户密码;grant connect,resource to 用户;测试连接 conn mpi/1234删除表空间drop tablespace XX including contents and datafiles cascade constraints;//including contents 删除表空间的内容//cascade constraints同时删除tablespace中表的外键参照删除用户drop user USERNAME CASCADE;如提示ora-01940 无法删除已经连接会话的用户select username,sid,serial# from v$session where username like ‘HIP4‘找到要删除用户的sid,和serial，并删除alter system kill session‘532,4562‘-------------------------------------------su - oracle   -切换oracle用户sqlpus / as sysdba   -本地登录sqlplusselect * from dba_directories;  -查询路径drop directory dp_dir;   -删除目录create directory dp_dir as ‘/backup/dp_dir‘;  -创建目录grant read,write on directory dp_dir to public;  -赋权目录expdp xx/xx directory=dp_dir dumpfile=xxx.dmp schemas=xxx  --导出例  expdp ‘"/as sysdba"‘ directory=dp_dir dumpfile=xx1207.dmp schemas=xximpdp ‘"/as sysdba"‘ directory=dp_dir dumpfile=1112mdbyl.dmp   --导入.注意此处不加封 封号！！！！impdp ‘"/as sysdba"‘ directory=dp_dir dumpfile=1112mdbyl.dmp remap_schema=mdbyl:mdbyl3   --导入改名select file_name,tablespace_name from dba_data_files; --查询数据文件路径select username,default_tablespace from dba_users where username like ‘X%‘;  --模糊查询x开头的用户SELECT * FROM V$SESSION WHERE USERNAME=‘PINGTAI‘;alter system kill session ‘3406,1671‘;drop user PINGTAI cascade;---------------------------------------------------SELECT t.table_name,       t.colUMN_NAME,       t.DATA_TYPE || ‘(‘ || t.DATA_LENGTH || ‘)‘,       t1.COMMENTS  FROM User_Tab_Cols t, User_Col_Comments t1WHERE t.table_name = t1.table_name    AND t.column_name = t1.column_name(+);