How do I change a Text Field to a Date Field without losing the content values?

Question

Is there a way I can change a Text field to a Date field and not toast the data that is already there?

Answer 1

You should not lose any data which already exists in your fields when changing field types - but if you have anything but a UNIX timestamp stored in the existing text field, the Date fieldtype won't know what to do with the data.

UPDATE:

To update your existing fields from your current format (5/14/2013) to a timestamp for use with the Date fieldtype, put this code in a PHP-enabled template and run it (backup your database first of course):

<?php
    $this->EE =& get_instance();
    $current = $this->EE->db->query("
        SELECT entry_id, field_id_XX FROM exp_channel_data WHERE field_id_XX != ''
    ");
    foreach($current->result_array() as $row)
    {
        $timestamp = strtotime($row['field_id_XX']);
        $this->EE->db->query(
            $this->EE->db->update_string('exp_channel_data', array('field_id_XX' => $timestamp), 'entry_id='.$row['entry_id'])
        );  
    }
?>