Schema del DB (due entità, A e B)

BTable.class.php

<?php

/**
 * BTable
 * 
 * This class has been auto-generated by the Doctrine ORM Framework
 */
class BTable extends Doctrine_Table
{
    /**
     * Returns an instance of this class.
     *
     * @return object BTable
     */
    public static function getInstance()
    {
        return Doctrine_Core::getTable('B');
    }
    /**
     * Parte aggiunta
     */
    function construct()
    {
      // Imposto il criterio di sorting.
      $this->setOption('orderBy', 'sorting ASC');
    }

}

schema.yml

# Entity A
A:
  columns:
    name: string(255)

  relations:
    Bs:
      type: many
      class: B
      local: id
      foreign: a_id
      onDelete: CASCADE

# Entity B
B:
  columns:
    a_id: integer
    name: string(255)
    sorting: integer

  relations:
    A:
      local: a_id
      foreign: id
      type: one