I'm not sure you could call this a bug, but if you're validating uniqueness on a date field using MySQL it is something to be aware of.

In the installer: 'datum' is a ordinary date field (and not a datetime field. I didn't need hours and minutes)

function up_1()
{
    $this->createTable('meterreadingdates', "
      id,
      user_id,
      datum date
    ");
}

There should be only one record for every 'datum', so in the model is a validation on uniqueness.

class Meterreadingdate extends ActiveRecord
{
    var $belongs_to = 'user';
    var $has_many   = 'meterreadings';

    function validate(){
        $this->validatesUniquenessOf('datum');
    }
}

But, here it comes, just before saving a new row Akelos checks the uniqueness of the 'datum' field thinking it's a datetime field.

From the $this-> meterreadingdate->dbug() :

SELECT * FROM meterreadingdates WHERE meterreadingdates.datum = '2008-02-03 00:00:00' LIMIT 1

.. because of the ' 00:00:00' bit an already existing record is not found. (at least not using MySQL)

Changing the column type from date to datetime solves the problem of course.

Okay, I'll make a test and make a ticket in the Trac (somewhere next month though)