oracle数据库如何创建角色并对角色授予权限

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;