In the past, I have done one to many or many to many relationship using hasmanycomplextablefield, ManyManyComplexTableField. However, is it possible to assign the same page type to itself to form a many to many relationship. For instance you create a page type named. 'Article page' then in its own class add many to many relationship.

<?php
/**
* Defines the ArticlePage page type
*/

class ArticlePage extends Page {
   static $db = array(
      'Headline' => 'Text',
      'Summary' => 'Text'
   );
   static $has_one = array(
      
   );
   static $has_many = array(
      'MyArticlePages' => 'ArticlePage',
      'RelateToArticlePage' => 'ArticlePage'
);
   
   
   function getCMSFields() {
      $fields = parent::getCMSFields();
      
      $fields->addFieldToTab('Root.Content.Main', new TextField('Headline'), 'Content');
      $fields->addFieldToTab('Root.Content.Main', new TextField('Summary'), 'Content');
                  
      $tablefield = new ManyManyComplexTableField(
         $this,
         'MyArticlePages',
         'ArticlePage',
         array(
            'Headline' => 'Page Headline',
            'Summary' => 'Summary'
         ),
         'getCMSFields_forPopup',
          null,
          'Headline'
      );
      $tablefield->setAddTitle( 'A Related Page' );
      
      $tablefield->setPermissions(array(
      ));

      
      $fields->addFieldToTab( 'Root.Content.Related', $tablefield );
            
      return $fields;
   }
   
}

class ArticlePage_Controller extends Page_Controller {
   
}
?>

I got the following error:

Fatal error: Cannot instantiate abstract class Object in /var/www/vhosts/isnt-test.com/httpdocs/sapphire/core/Object.php on line 229

Has anyone done this before? thank you for taking the time to read this.

Add this in as the filter if don't want the current region child page show up in the complexTableField as a option to link to itself.

"RegionChildPage.ID != $this->ID", //To the filter section.

Here is the full view of the ManyManyComplexTableField

$tablefield = new ManyManyComplexTableField(
         $this,
         'MyRegionChildPages',
         'RegionChildPage',
         array(
            'Headline' => 'Page Headline',
            'Summary' => 'Summary'
         ),
         'getCMSFields_forPopup',
          "RegionChildPage.ID != $this->ID",
          'Headline'
      );

Try this:
"TrackProductID=$this->ID OR TrackProductID IS NULL"