Abstract: A method of searching a second database comprising A) receiving a summary document generated by the first database, the summary document comprising a list of returned first database subject keys, representing the returned first database subjects, the list further including at least one identifier associated with the returned first database subjects; B) reading the summary document and generating one or more second database query options for searching for second database subjects that have relationships to the returned first database subjects corresponding to the at least one identifier; C) receiving a second database query in accordance with said one or more second database query options; D) receiving said returned first database subjects; E) using said returned first database subjects, searching said second database in accordance with said second database query options.