text: -- auto-generated definition
  create table operation
  (
      id          int auto_increment
          primary key,
      user_       int                                   not null,
      timestamp   timestamp default current_timestamp() not null on update current_timestamp(),
      product     int                                   null,
      description varchar(255)                          null,
      constraint operation_product_id_fk
          foreign key (product) references product (id)
              on delete set null,
      constraint operation_user__id_fk
          foreign key (user_) references user_ (id)
  );
  
  