Actions:

• create user
• delete user
• create role
• delete role
• grant permision to role
• revoke permision from role
• add user to role
• remove user from role
• ask if user has permission(s)

permission-userID

user -> role -> permission user -> permission?

user_permissions table: permission, userID

user_roles table: roleName, userID

role_permissions table: roleName, permission

delete role => remove permissions from all users who have this role

delete user => remove user from all roles => remove permissions from user

delete permission => remove permission from roles (and maybe users?)

create table users ( user_id text not null constraint users_pk primary key );

create unique index users_user_id_uindex on users (user_id);