Patent ID: 7577694

Claim:
A database management system comprising: a processor; an acceptance section; a plurality of database management executors, connected to a plurality of existing storages, wherein, in a first operation, each of the plurality of existing storages stores a table of data having a plurality of data items, and wherein said table of data is determined according to a predetermined division rule and stored in the existing storages; rebalance operation means for executing a second operation by determining data to be moved between the existing storages due to any one of addition and disconnection of an additional storage to be connected, according to said division rule, and by moving the data that was determined to be moved; means for accepting any one of a search request, update request, delete request or insert request to said table of data at said acceptance section of said database management system during execution of the second operation by the rebalance operation means; means, in response to any one of said search request, update request and delete request that has been accepted, for parallelly executing search, update and delete operations over the existing storages connected to said database management system executors, and after completion of parallelly executing said search, update and delete operations over said existing storages, parallelly executing said search, update and delete operations over said additional storage added to said existing storages of said database management system executors; and means, in response to the insert request that was accepted, for determining a storage destination of data to be inserted in said additional storage, according to said division rule, and for inserting the data to be inserted in the storage destination that was determined.