title: H2 database: referring to a table in root schema from a foreign key constraint
body: <p>Given a table in root schema:</p>
  
  <pre><code>CREATE TABLE user (
      username VARCHAR(50),
      password VARCHAR(50));
  </code></pre>
  
  <p>and a table in <code>Quiz</code> schema:</p>
  
  <pre><code>CREATE TABLE Quiz.Results (
      username VARCHAR(50),
      points INT, 
      FOREIGN KEY (username) REFERENCES user(username));
  </code></pre>
  
  <p>I'm unable to actually create the foreign key, because the database claims the table <code>user</code> does not actually exist. Neither can I subsequently add the foreign key:</p>
  
  <pre><code>ALTER TABLE QUIZ.RESULTS
      ADD FOREIGN KEY (username) REFERENCES user (username) 
  </code></pre>
  
  <p>Both tables are, of course, stored in the same database.</p>
  
  <p>Since this is just a piece of homework, I'm more than happy to simply skip adding a foreign key. But I'm curious if this is indeed a limitation in H2, a bug, or if it works as intended. </p>
  
  <p>Can I somehow refer to table <code>user</code> outside the <code>quiz</code> schema?</p>