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Error: 'ParentID' appears twice



Shane Garelja

16 May 2008 at 11:31am (Last edited: 16 May 2008 12:03pm), Community Member, 18 Posts


I'm trying to create a new dataobject called Category. You can have categories and sub-categories so I'm trying to code it so that a Category object can have another Category object as it's parent (has_one) or it can have multiple "Category" objects (has_many).

I thought this would be quite simple but I can't work out how to get around this error (see title of post). This is what I have so far:

class Category extends DataObject {
   static $db = array(
      'Name' => 'Text',      
      "Type" => "Enum('Business, Event, Community', 'Business')"      
   static $default_sort = "Name";

static $has_one = array(   
'Parent' => 'Category'
   static $has_many = array(
      'Children' => 'Category'

   function getCMSFields_forPopup() {
      $fields = new FieldSet();
      $fields->push( new TextField( 'Name' ) );      
      $fields->push( new DropdownField("ParentID", "Parent Category", array()));      
      $fields->push( new DropdownField("Type", "Type",
            'Business' => 'Business',
            'Event' => 'Event',
            'Community' => 'Community'
      return $fields;

I can see that it's not happy with the field I'm trying to create where you select the parent Category (or leave empty if it's a top-level category). How do I do this?? Are there any examples I can look at in one of the modules? I looked at the Post object in the Forum module but it's slightly different.