The invention provides information concerning records that cannot be retrieved on a search path among databases when the retrieval of search keys for other related databases and records is carried out in a plurality of databases in a chain-reactive manner. In the course of retrieving search keys and records in a chain-reactive manner up to a terminal database, information for identifying a group of search keys and a group of records retrieved through a series of retrieval processing is outputted in one line or one column of a table. When the record retrieved from a certain database in the chain-reactive search procedure does not contain a search key to be entered into a subsequent database, information for identifying a record that does not contain the search key and information for identifying a database having the record is outputted.