create table topics (
    id int not null auto_increment,  
    name varchar(50) default null,  
    feed_size int default null, 
    primary key (id)
);

create table topic_sources (
    topic_id int not null,
    platform varchar(50) not null,
    keywords varchar(50) default null,
    primary key (topic_id,platform)
);

create table reference_types (
    reference_type_id int not null auto_increment,
    type_label varchar(50) default null,
    abbreviation varchar(50) default null,
    description varchar(50) default null,
    primary key (reference_type_id)
);

create table reference_codes (
    reference_type_id int not null,
    reference_code int not null,
    code_label varchar(50) default null,
    abbreviation varchar(50) default null,
    description varchar(50) default null,
    primary key (reference_type_id, reference_code)
);

create table products (
    id int not null auto_increment,
    name varchar(50) default null,
    primary key (id)
);

create table tariffs (
    tariff_id int not null,
    start_date date not null,
    amount integer(11) default null,
    created_at timestamp,
    updated_at timestamp,
    primary key (tariff_id, start_date)
);

create table product_tariffs (
    product_id int not null,
    tariff_id int not null,
    tariff_start_date date not null,
    primary key (product_id, tariff_id, tariff_start_date)
);

create table suburbs (
    city_id int not null,
    suburb_id int not null,
    name varchar(50) not null,
    primary key (city_id, suburb_id)
);

create table streets (
    id int not null auto_increment,
    city_id int not null,
    suburb_id int not null,
    name varchar(50) not null,
    primary key (id)
);

create table users (
    id int not null auto_increment,
    name varchar(50) not null,
    primary key (id)
);

create table articles (
    id int not null auto_increment,
    name varchar(50) not null,
    primary key (id)
);

create table readings (
    id int not null auto_increment,
    user_id int not null,
    article_id int not null,
    rating int not null,
    primary key (id)
);

create table groups (
    id int not null auto_increment,
    name varchar(50) not null,
    primary key (id)
);

create table memberships (
    user_id int not null,
    group_id int not null,
    primary key  (user_id,group_id)
);

create table membership_statuses (
    id int not null auto_increment,
    user_id int not null,
    group_id int not null,
    status varchar(50) not null,
    primary key (id)
);

create table departments (
    department_id int not null,
    location_id int not null,
    primary key (department_id, location_id)
);

create table employees (
    id int not null auto_increment,
    department_id int default null,
    location_id int default null,
    primary key (id)
);

create table comments (
    id int not null auto_increment,
    person_id int default null,
    shown int default null,
    person_type varchar(100) default null,
    hack_id int default null,
    primary key (id)
);

create table hacks (
    id int not null auto_increment,
    name varchar(50) not null,
    primary key (id)
);

create table restaurants (
    franchise_id int not null,
    store_id int not null,
    name varchar(100),
    lock_version int default 0,
    primary key (franchise_id, store_id)
);

create table restaurants_suburbs (
    franchise_id int not null,
    store_id int not null,
    city_id int not null,
    suburb_id int not null
);

create table dorms (
    id int not null auto_increment,
    primary key(id)
);

create table rooms (
    dorm_id int not null,
    room_id int not null,
    primary key (dorm_id, room_id)
);

create table room_attributes (
    id int not null auto_increment,
    name varchar(50),
    primary key(id)
);

create table room_attribute_assignments (
    dorm_id int not null,
    room_id int not null,
    room_attribute_id int not null
);

create table students (
    id int not null auto_increment,
    primary key(id)
);

create table room_assignments (
    student_id int not null,
    dorm_id int not null,
    room_id int not null
);

create table seats (
  flight_number int not null,
  seat          int not null,
  customer      int,
  primary key (flight_number, seat)
);

create table capitols (
  country varchar(100) default null,
  city varchar(100) default null,
  primary key (country, city)
);

create table products_restaurants (
  product_id int not null,
  franchise_id int not null,
  store_id int not null
);

create table employees_groups (
  employee_id int not null,
  group_id int not null
);