1. Apparatus for responding to a request, the request including one or more specifiers referring to objects belonging to a plurality of objects thereof in a distributed database system that includes a plurality of database systems, the plurality including a first database system and a second database system and the apparatus comprising: a query analyzer that determines whether the request includes a specifier that cannot be interpreted in the first database system; and a redirector which responds to the request when the query analyzer determines that the request includes the specifier that cannot be interpreted in the first database system by causing the request to be executed at least in part in the second database system, the request being executed in the first database system when the query analyzer does not determines that the request includes the specifier that cannot be interpreted in the first database system.