设置角色权限
-- Grant/Revoke role privileges
grant connect to alef;
grant resource to alef;
-- Grant/Revoke system privileges
grant alter session to alef;
grant create cluster to alef;
grant create database link to alef;
grant create sequence to alef;
grant create session to alef;
grant create synonym to alef;
grant create table to alef;
grant create view to alef;
grant dba to alef;