An apparatus is provided with base table storage sections that store base tables and delta tables for the base tables, a summary table storage section that stores a summary table for storing results of queries to a plurality of base tables and delta information about the summary table, delta data processing sections that insert delta data of the base tables into the delta tables, and a delta computation processing section that generates delta information about the summary table. The delta computation processing section is provided with a generation section that generates delta information about a specified base table on the basis of an update that has been performed for the base table, in a situation where a subsequent update of the specified base table is permitted; and a control section that performs control so that, when a different base table is specified, delta information is generated in a different transaction.