drupal 6 to drupal 7 - schema - datetime issue

I have a module.install file with datetime column as like
below in drupal 6

'startdate' => array(
'description' => 'The start date.',
'type' => 'datetime',
),
'enddate' => array(
'description' => 'The end date.',
'type' => 'datetime',
),

Placed that module in drupal 7 and when I try to install the module I got the following error:

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DEFAULT NULL COMMENT 'The start date.',

Based on information from https://drupal.org/node/866340

We have use the datetime as below:

'startdate' => array(
'description' => 'The start date.',
'mysql_type' => 'datetime',
),
'enddate' => array(
'description' => 'The end date.',
'mysql_type' => 'datetime',
),

same way for tinyint specify mysql_type=>'tinyint'.