title: Datetime type in Drupal 7 schema
body: <p>I'm writing a new Drupal 7 module (Drupal 7.10, Date 7.x-2.0-rc1 installed, Schema 7.x-1.0-beta3 installed)
  i defined a table in mymodule.install:</p>
  
  <pre><code>$schema['museums_tickets']= array(
      'fields' =&gt; array(
          'nid' =&gt; array(
          'type' =&gt; 'int',
          'unsigned' =&gt; TRUE,
          'not null' =&gt; TRUE,
      ),
      'day' =&gt; array(
          'type' =&gt; 'datetime', 
          'mysql_type' =&gt; 'DATETIME',
          'not null' =&gt; TRUE,
      ),
      'tickets' =&gt; array(
          'type' =&gt; 'int',
          'unsigned' =&gt; TRUE,
          'not null' =&gt; TRUE,
          ),
      'ticket_code' =&gt; array(
              'type' =&gt; 'varchar',
              'length' =&gt; 32,
              'not null' =&gt; TRUE, 
              'default' =&gt; '',
          ),
      ),
      'primary key' =&gt; array('nid', 'day','ticket_code'),
  );
  </code></pre>
  
  <p>but i obtain the following errors:</p>
  
  <pre><code>Field museums_tickets.day: no Schema type for mysql type datetime.
  museums_tickets.day: no type for Schema type datetime.
  Field museums_tickets.day: no Schema type for type datetime. 
  </code></pre>
  
  <p>The same applies if i use</p>
  
  <pre><code>'type' =&gt; 'datetime:normal',
  </code></pre>
  
  <p>I would like to know how to solve this problem. 
  I don't want to store dates as timestamp, since another person wrote a lot of code and obviously i don't want to rewrite all.
  I already looked at <a href="https://stackoverflow.com/questions/8170779/drupal-7-custom-schema-error-datetime">drupal 7 custom schema error datetime</a> but the answer doesn't work.
  Maybe i'm doing something wrong, but i don't find what.</p>
  
  <p>Thank you in advance.</p>