text: -- @testpoint: opengauss关键字constraint_name(非保留)，作为角色名，部分测试点合理报错
  
  
  --关键字不带引号-成功
  drop role if exists constraint_name;
  create role constraint_name with password 'gauss@123' valid until '2020-12-31';
  
  --关键字带双引号-成功
  drop role if exists "constraint_name";
  create role "constraint_name" with password 'gauss@123' valid until '2020-12-31';
  
  --关键字带单引号-合理报错
  drop role if exists 'constraint_name';
  create role 'constraint_name' with password 'gauss@123' valid until '2020-12-31';
  
  --关键字带反引号-合理报错
  drop role if exists `constraint_name`;
  create role `constraint_name` with password 'gauss@123' valid until '2020-12-31';
  
  --清理环境
  drop role if exists constraint_name;
  drop role if exists "constraint_name";