リスト1　create_table.ddl

drop table goods;
drop table category;
drop table price;

create table category (
    id integer primary key,
    name varchar(200) not null
);

create table price (
  id integer primary key,
  cost int,
  retail int
);

create table goods (
  id integer primary key,
  category_id integer references category (id),
  price_id integer references price (id),
  sample varchar(200),
  name varchar(200) not null,
  date date,
  description varchar(200)
);