[development] submitting date values to database using date_popup type form api

Hi, I have a form element called date in my module file like this .. $format='Y-m-d'; $form['date'] = array( '#type' => 'date_popup', '#title' => t(' Date'), '#date_format' => $format, ); date pop up Is coming fine and I can select date easily. Issue ahead me is to submit this date to database and show it in my edit form with default value which I submitted in databse. How I can submit this date to database (which is the better data type in table for this field? Is it int or date or datetime in mysql?) and retvieve it in Year-Month-date format to show on screen. I am new baby to drupal .Please help me guys. Mahi,