title: sql CHECK constraint not working properly
body: <p>I have created a table schedule with a check constraint:</p>
  
  <pre><code>mysql&gt; create table schedule(order_date date, dely_date date
                               check(dely_date&gt;order_date));
  Query OK, 0 rows affected (0.50 sec)
  </code></pre>
  
  <p>When I insert a value which violates check constraint, sql reports no error.</p>
  
  <pre><code> mysql&gt; insert into schedule values('2015-11-20','2014-12-25');
  Query OK, 1 row affected (0.10 sec)
  
  mysql&gt; select * from schedule;
  +------------+------------+
  | order_date | dely_date  |
  +------------+------------+
  | 2015-11-20 | 2014-12-25 |
  +------------+------------+
  1 row in set (0.00 sec)
  </code></pre>
  
  <p>I have inserted a dely_date which comes before order_date.</p>