学步园

1、privilege types:system ,object
2、grant revoke any 
3、grant create session to usr1 with admin option;授权传递,撤销无法传递

4、select any table

5、grant select on t to u3;
6、grant grant any object privileges to u2;
7、with grant option 授权，撤销都有传递性

数据字典：

system privilege:

                               dba_sys_privs  

                               session_privs
object privilege:

                               dba_tab_privs

                               dba_col_privs