Abstract: Data of a distributed, compressed and restored index (D-CRX) related to a correspondence relation between a key value related to a registration request and NID, and data of a distributed and compressed result set cache (D-CRS) related to a correspondence relation between a distributed row identifier (RID) taking a unique value every column in a table constituting a distributed database and the NID are distributed and stored in each of slave nodes 15, 17 and 19. When the data of the D-CRX is to be distributed and stored in each of the slave nodes 15, 17 and 19, the same slave node as the slave node determined as a storage location for the data of the D-CRS is determined as a storage location of the data of the D-CRX in relation to the data of the D-CRX to which the same NID as the NID indicated by the data of the D-CRS is assigned.

Abstract: Data of distributed shared NID (DSN) related to a correspondence relationship between a key value to be an actual value and a key value identifier (NID) taking a unique value within a range of a data type possessed by the key value in a whole distributed database is classified every data type and is distributed and stored in each of slave nodes. When the data of the DSN is to be distributed and stored in each of slave nodes 15, 17 and 19, one of the slave nodes which serves as a storage location is determined from the slave nodes 15, 17 and 19 based on a key value related to a registration request.

Abstract: Provided are categorizing unit (2) which analyzes whether or not a character string contained in text data matches any of member character strings of a category provided as parameters, and acquires a category character string provided as a parameter for a name scale of the matched member character string; and an integration unit (3) which integrates the acquired category character string to a relational database. A category character string converted from the text data can be arbitrarily changed by a parameter, and a member character string used for assessing the match at the time of converting the text data to the category character string can be also changed arbitrarily by a parameter, and thereby, the text data can be flexibly categorized interactively.