CREATE TABLE theaters(
  name varchar2(50) PRIMARY KEY,
  city varchar2(20),
  state varchar2(2),
  zip number(5),
  phone varchar(15)
);

CREATE TABLE movies(
  title varchar2(20) PRIMARY KEY,
  rating DECIMAL(2,1),
  length number(4),
  releaseDate date,
  check (rating >= 0 and rating <= 10),
  check (length > 0),
  check (releaseDate > '01-JAN-1990')
);

CREATE TABLE shownAt(
  theaterName varchar(50),
  movieTitle varchar(20),
  foreign key (theaterName) references Theaters(name)
);