oracle表的简单操作步骤

 create table test_1(num number(2) not null,name VARCHAR2(20) not null,primary key(num));

 create table test_2 as select  from test_1;

 create table test_3 as select  from test_1 where 1=2; 

 drop table test_1

 SELECT  FROM user_tab_columns t WHERE t.TABLE_NAME='TEST_1';

 --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 dba_users; 
 --查看你能管理的所有用户！
 select  from all_users; 
 -- 查看当前用户信息 ！
 select  from user_users;