create table users (
     user_id         integer not null primary key,
     login           text,
     passwd          text 
);

create table role_types (
     role_type_id   integer not null primary key,
     role_type      text 
);

create table role_map (
       role_mapping_id   integer not null primary key,
       role_type_id      integer not null
                         references role_types(role_type_id)
                         on delete cascade,
       user_id           integer not null
                         references users(user_id) 
                         on delete cascade
);