private function fields($class) { if ($class == $this->_class) { return $this->_class . '.*'; } else { $tree = Model::getISATree($class); $fields = array(); foreach ($tree as $c) { foreach (Model::getFieldNamesFor($c) as $field) { // Fix duplicate columns problem (does not occur in SQLite, but does in MySQL) if (! array_key_exists($field, $fields)) $fields[$field] = $c . '.'.$field; } } return implode(', ', $fields); } }