A database system, a computer executable method, a computer executable program for the database system, and a method for updating an indexing tables in a database system are provided. The database system comprises a database storing item tables of items appended by timestamps. Each of the items is further categorized by timestamp into the tables, and the item tables are indexed by indexing data. The database system further comprises an indexing table for the indexing data, listing the earliest timestamp of the item table together with the indexing data and a system manager for searching the item tables using the indexing table and a maintenance module for the indexing table.