public static function from($queryClassAndAlias) { list($class, $alias) = ModelCriteria::getClassAndAlias($queryClassAndAlias); $queryClass = $class . 'Query'; if (!class_exists($queryClass)) { throw new PropelException('Cannot find a query class for ' . $class); } $query = new $queryClass(); if ($alias !== null) { $query->setModelAlias($alias); } return $query; }