title: ORA-00907: missing right parenthesis, all parenthesis have been closed but still not working
body: <p>I want to create two tables <code>Publisher</code> and <code>Book</code>. Here are the SQL statements for creating the tables.</p>
  <p>I want to create a foreign key constraint in the Book table. I'm not sure why it's throwing this error. I cross-checked all the parenthesis. The syntax seems to be fine but it's not creating the table.</p>
  <pre><code>CREATE TABLE Publisher
  (
      pub_name varchar2(128) PRIMARY KEY, 
      phone integer, 
      address varchar2(20)
  );
  
  
  CREATE TABLE Book
  (
      book_id integer NOT NULL PRIMARY KEY,
      title varchar2(256),
      pub_year number(4) UNSIGNED,
      pub_name REFERENCES Publisher(pub_name) ON DELETE CASCADE ON UPDATE CASCADE
  );
  </code></pre>