---

mysql> create database lr21;
Query OK, 1 row affected (0.05 sec)

mysql> use lr21;
Database changed

-- авторы
mysql> create table authors (
    -> id integer primary key auto_increment,
    -> first_name varchar(100) not null,
    -> last_name varchar(100) not null
    -> );
Query OK, 0 rows affected (0.02 sec)

-- читатели
create table readers (
id integer primary key auto_increment,
first_name varchar(100) not null,
last_name varchar(100) not null
age int not null
);

-- жанры
create table genres (
id integer primary key auto_increment,
name_genre varchar(100) not null
);

-- рейтинг
create ratings (
id integer primary key auto_increment,
book_id int not null,
readers_id int not null,
rating decimal(10,2) not null,
foreign key(book_id) references books(id)
);


create table books (
id integer primary key auto_increment,
name_book varchar(100) not null,
author_id int not null,
genre_id int not null,
price decimal(10,2) not null,
publish_year datetime not null,
foreign key(author_id) references authors(id),
foreign key (genre_id) references genres(id)
);