Database system, method, program for the database system, and a method for updating an indexing tables in a database system

The database search method in a database system, said database system comprising a computer including a CPU, a memory, and a storage device, said database being stored in said storage device, said database search method making said computer execute the steps of:

• storing item tables of items appended by timestamps in a database, said items each being categorized by timestamp into said tables, and said item tables being indexed by indexing data;
• storing an indexing table for said indexing data, listing the earliest timestamp of said item table together with said indexing data;
• searching said item tables referring said indexing table, said indexing table being repaired with respect to time evolution by a maintenance module, said maintenance module executing further steps of;
• monitoring the correlation between said item tables and said indexing table, invoking from said item table said newest timestamp together with said indexing data, and
• examining said correlation of said indexing table using said invoked timestamp and said indexing data as examination keys.

A computer executable program for a database search method in a database system, said database system comprising a computer including a CPU, a memory, and a storage device, said database being stored in said storage device, said program making said computer execute the steps of:

• storing item tables of items appended by timestamps in a database, said items each being categorized by timestamp into said tables, and said item tables being indexed by indexing data;
• storing an indexing table for said indexing data, listing the earliest timestamp of said item table together with said indexing data;
• searching said item tables referring said indexing tables, said indexing table being repaired with respect to time evolution by a maintenance module, said maintenance module executing further steps of;
• monitoring a correlation between said item tables and said indexing table, invoking from said item table said newest timestamp together with said indexing data, and examining said correlation of said indexing table using said invoked timestamp and said indexing data as examination keys.