where($field_name, "=", $id)->find(); if (!$model->loaded()) { throw new Exception("@todo MISSING_MODEL $model_name:$id"); } self::$cache[$model_name][$field_name][$id] = $model; } return self::$cache[$model_name][$field_name][$id]; } static function clear() { self::$cache = array(); } static function set($model) { self::$cache[$model->object_name][$model->primary_key][$model->{$model->primary_key}] = $model; } }