title: h2 does not enforce NOT NULL in MySQL compatibility mode
body: <p>In MySQL compatibility mode, the following SQL succeeds and returns 0:</p>
  
  <pre><code>CREATE TABLE test2 (i INTEGER NOT NULL);
  INSERT INTO test2 VALUES (NULL);
  SELECT * FROM test2;
  </code></pre>
  
  <p>It fails as expected in the default mode.  It also fails with MySQL 5.5 / InnoDB.  Does "MySQL compatibility" actually mean "MyISAM compatibility"?</p>