public function getFieldAliases($className) {
        $fieldAliases= array ();
        if ($className= $this->loadClass($className)) {
            if ($ancestry= $this->getAncestry($className)) {
                for ($i= count($ancestry) - 1; $i >= 0; $i--) {
                    if (isset ($this->map[$ancestry[$i]]['fieldAliases'])) {
                        $fieldAliases= array_merge($fieldAliases, $this->map[$ancestry[$i]]['fieldAliases']);
                    }
                }
            }
            if ($this->getInherit($className) === 'single') {
                $descendants= $this->getDescendants($className);
                if ($descendants) {
                    foreach ($descendants as $descendant) {
                        $descendantClass= $this->loadClass($descendant);
                        if ($descendantClass && isset($this->map[$descendantClass]['fieldAliases'])) {
                            $fieldAliases= array_merge($fieldAliases, array_diff_key($this->map[$descendantClass]['fieldAliases'], $fieldAliases));
                        }
                    }
                }
            }
        }
        return $fieldAliases;
    }