Administrators Guide上有很多很好的实验，我会陆续的实验
SQL> connect nba/nba@game
已连接。
SQL> create table admin_test(name varchar2(20));
表已创建。
SQL> connect nba/nba@game as sysdba
已连接。
SQL> select * from admin_test;
select * from admin_test
*
ERROR 位于第 1 行:
ORA-00942: 表或视图不存在
When you connect with SYSDBA or SYSOPER privileges, you connect with a default
schema, not with the schema that is generally associated with your username. For
SYSDBA this schema is SYS; for SYSOPER the schema is PUBLIC.
用as sysdba或者as sysopen，就会连接默认的schema，并不是你用户名关联的schema。
所以as SYSDBA的用户是SYS，as SYSOPER的用户是PUBLIC
Having connected as SYSDBA, user oe now references the SYS schema, but the table
was created in the ××× schema.
该实验中在nba schema中建表，当你以SYSDBA身份登录时，并不能访问到这张表，因为AS SYSDBA会连接
默认的SYS schema
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/22111412/viewspace-611455/ ，如需转载，请注明出处，否则将追究法律责任。
