create user 'test_user'@'localhost';
create user 'test_role1'@'';
update mysql.user set is_role='Y' where user='test_role1';
insert into mysql.roles_mapping (HostFk, UserFk, RoleFk) values ('localhost',
'test_user',
'test_role1');
select user, host from mysql.user where user not like 'root';
user	host
test_role1	
test_user	localhost
select * from mysql.roles_mapping;
HostFk	UserFk	RoleFk
localhost	test_user	test_role1
flush privileges;
grant select on mysql.* to test_role1@'';
grant insert, delete on mysql.roles_mapping to test_role1@'';
grant reload on *.* to test_role1@'';
select * from mysql.roles_mapping;
ERROR 42000: SELECT command denied to user 'test_user'@'localhost' for table 'roles_mapping'
set role test_role1;
select * from mysql.roles_mapping;
HostFk	UserFk	RoleFk
localhost	test_user	test_role1
insert into mysql.user (user, host) values ('Dummy', 'Dummy');
ERROR 42000: INSERT command denied to user 'test_user'@'localhost' for table 'user'
insert into mysql.roles_mapping (HostFk, UserFk, RoleFk) values ('localhost',
'test_user',
'test_role2');
delete from mysql.roles_mapping where RoleFk='test_role2';
use mysql;
set role none;
use mysql;
ERROR 42000: Access denied for user 'test_user'@'localhost' to database 'mysql'
select * from mysql.roles_mapping;
ERROR 42000: SELECT command denied to user 'test_user'@'localhost' for table 'roles_mapping'
insert into mysql.user (user, host) values ('Dummy', 'Dummy');
ERROR 42000: INSERT command denied to user 'test_user'@'localhost' for table 'user'
insert into mysql.roles_mapping (HostFk, UserFk, RoleFk) values ('localhost',
'test_user',
'test_role2');
ERROR 42000: INSERT command denied to user 'test_user'@'localhost' for table 'roles_mapping'
delete from mysql.roles_mapping where RoleFk='test_role2';
ERROR 42000: DELETE command denied to user 'test_user'@'localhost' for table 'roles_mapping'
drop user 'test_user'@'localhost';
revoke select on mysql.* from test_role1@'';
revoke insert, delete on mysql.roles_mapping from test_role1@'';
delete from mysql.user where user='test_role1';
delete from mysql.roles_mapping where RoleFk='test_role1';
flush privileges;