<?php

    /**
     * Get node defined by $where
     *
	 * @param string|array|Zend_Db_Table_Select|Zend_Db_Table_Row $where OPTIONAL
	 * 	  An SQL WHERE clause or Zend_Db_Table_Select object. Or Row object.
     * @return Zend_Db_Table_Row_Abstract
     */
    protected function _getNode($where)
    {
        if (!($where instanceof Zend_Db_Table_Row_Abstract)) {
            if (is_int($where)) {
                $where = "{$this->_relativeKeyColumn} = $where";
            }

            $node = $this->fetchRow($where);
            if ($node === null) {
                return null;
            }
        } else {
            $node = $where;
        }

        return $node;
    }