Patent ID: 7587432

Claim:
A method for data maintenance in an offline-distributed database network system, the database network system comprising a central system having a central database, and a plurality of node systems having local databases, the local databases capable of containing different subsets of data from the central database, the method comprising: recording change information relating to data stored in at least one of the central and local databases in the database network system in at least one of the plurality of node systems; determining which, if any, of said change information relating to data should be replicated into a replication object; transmitting the a replication object, if an online connection is available, from said at least one of the node systems to the central system or from the central system to said at least one of the node systems; and updating at least one lookup table in accordance with the change information of the replication object, the lookup table identifying local databases requiring updating in response to said change information when an online connection for such local databases becomes available, wherein said at least one lookup table includes a first-type lookup table and a second-type lookup table, the first-type lookup table containing an allocation between types of structure of replication objects and node systems, the second-type lookup table containing an allocation between entities of replication objects and node systems, the node systems being for the replication object in the database network system, determining, in a replication algorithm, node systems for the replication object, and wherein the replication algorithm is carried out by at least one of first and second replication algorithms depending on the type of structure of the replication object, the first replication algorithm being used to allocate a first subset of the replication object to the node systems as a function of the type of structure of the replication object, using the first-type lookup table, and the second replication algorithm being used to allocate a second subset other than the first subset of the replication object to the node systems as a function of an entity of the replication object, using the second-type lookup table.