目标： 1、创建角色test1_role, 授予create session 权限
2、创建角色test2_role,授予create procedure, create sequence, create synonym, create trigger, create type, create view 权限
create role test1_role;
grant create session to test1_role;
create role test2_role;
grant create procedure, create sequence, create synonym, create table, create trigger, create view to test2_role;