--- /dev/null
+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * Object Relational Mapping (ORM) "tree" extension. Allows ORM objects to act
+ * as trees, with parents and children.
+ *
+ * $Id: ORM_Tree.php 3923 2009-01-22 15:37:04Z samsoir $
+ *
+ * @package ORM
+ * @author Kohana Team
+ * @copyright (c) 2007-2008 Kohana Team
+ * @license http://kohanaphp.com/license.html
+ */
+class ORM_Tree_Core extends ORM {
+
+ // Name of the child
+ protected $ORM_Tree_children;
+
+ // Parent keyword name
+ protected $ORM_Tree_parent_key = 'parent_id';
+
+ /**
+ * Overload ORM::__get to support "parent" and "children" properties.
+ *
+ * @param string column name
+ * @return mixed
+ */
+ public function __get($column)
+ {
+ if ($column === 'parent')
+ {
+ if (empty($this->related[$column]))
+ {
+ // Load child model
+ $model = ORM::factory(inflector::singular($this->ORM_Tree_children));
+
+ if (array_key_exists($this->ORM_Tree_parent_key, $this->object))
+ {
+ // Find children of this parent
+ $model->where($model->primary_key, $this->object[$this->ORM_Tree_parent_key])->find();
+ }
+
+ $this->related[$column] = $model;
+ }
+
+ return $this->related[$column];
+ }
+ elseif ($column === 'children')
+ {
+ if (empty($this->related[$column]))
+ {
+ $model = ORM::factory(inflector::singular($this->ORM_Tree_children));
+
+ if ($this->ORM_Tree_children === $this->table_name)
+ {
+ // Load children within this table
+ $this->related[$column] = $model
+ ->where($this->ORM_Tree_parent_key, $this->object[$this->primary_key])
+ ->find_all();
+ }
+ else
+ {
+ // Find first selection of children
+ $this->related[$column] = $model
+ ->where($this->foreign_key(), $this->object[$this->primary_key])
+ ->where($this->ORM_Tree_parent_key, NULL)
+ ->find_all();
+ }
+ }
+
+ return $this->related[$column];
+ }
+
+ return parent::__get($column);
+ }
+
+} // End ORM Tree
\ No newline at end of file