title: How to prevent empty values of enum column in MySQL
body: <pre><code>mysql&gt; CREATE TABLE foo ( f ENUM('a', '123') );
  
  mysql&gt; insert into foo(f) value(3);
  Query OK, 1 row affected, 1 warning (0.00 sec)
  
  mysql&gt; select * from foo;
  +------+
  | f    |
  +------+
  |      |
  +------+
  </code></pre>
  
  <p>How to make it produce a failure when inserting a value out of range?</p>