RedBeanPHP also supports self-referential one-to-many and many-to-many relationships. In RedBeanPHP terminology these are called trees. Here is an example, let's decorate a christmas tree with some candy canes:
$cane = R::dispense('cane',10);
$cane[1]->ownCane = array( $cane[2], $cane[9] );
$cane[2]->ownCane = array( $cane[3], $cane[4] );
$cane[4]->ownCane = array( $cane[5],
$cane[7], $cane[8] );
$cane[5]->ownCane = array( $cane[6] );
$id = R::store($cane[1]);
$root = R::load('cane',$id);
echo $root->ownCane[2]->ownCane[4]
->ownCane[5]->ownCane[6]->id;
//outputs: 6
In fact trees are just a special case of lists.
A Tree is the RedBeanPHP version of a self-referential relationship.
RedBeanPHP Easy ORM for PHP © 2013 Gabor de Mooij and the RedBeanPHP community - Licensed New BSD/GPLv2