Patent ID: 8271440

Claim:
An apparatus to refresh a summary table that stores results of a query to a plurality of base tables, the apparatus comprising: a manager to modify multiple base tables among said plurality of base tables between consecutive updates to said summary table and prior to a predetermined time point; a generator configured to generate delta information for each of said modified base tables to reflect in the summary table changes made before the predetermined time point in the multiple modified base tables, wherein said changes are reflected in the summary table in multiple transactions, one transaction for each modified base table, wherein each transaction corresponds to a different specified modified table designated among the modified tables, wherein the specified modified base table is permitted to be changed after the predetermined time point concurrent with a transaction refreshing the summary table for said specified base table and other base tables are prevented from being changed while changes are reflected in the summary table; and a controller configured to control the generator to generate delta information for the summary table by a different transaction when a different base table is specified among the multiple modified base tables.