select * from dba_users; 查看数据库里面所有用户，前提是你是有dba权限的帐号，如sys,system
select * from all_users;  查看你能管理的所有用户！
select * from user_users; 查看当前用户信息 ！
select count(*) from user_tables ;查询有多少张表

oracle 11g 导出数据不全
alter system set deferred_segment_creation=true; 

创建表空间 创建用户名
create tablespace BW
datafile 'D:\Oracle\oradata\BW_.dbf'
size 50M
autoextend on next 50m maxsize 20480m;

create user tt_jsbw identified by tt_jsbw default tablespace BW
temporary tablespace temp;

导出数据
$exp  tt_jsbw/tt_jsbw@orcl  file=c:\fk.dmp log=c:\fk.log
给tt_jsbw赋予dba权限
grant dba to tt_jsbw
给tt_jsbw赋予会话权限
grant create session to tt_jsbw
导入数据
imp xld_portal_user/xld_portal_0927 fromuser=xld_portal_user touser=xld_portal_user file=xld_portal_user_20160927.dmp ignore=y

imp tt_jsbw/tt_jsbw fromuser=tt_jsbw touser=tt_jsbw file=xld_portal_user_20160927.dmp ignore=y