Patent ID: 6374262
Filing Date: 2002-04-16
Classification: G06F,Y10S

Abstract:
A relational database synchronization method for synchronizing master data of a relational database held by a master machine with replica data which is a duplication of the master data and is held by each of a large number of replica machines, each replica machine usually operating with use of the replica data while in an off-line state with respect to the master machine, said relational database synchronization method comprising:connecting a replica machine to the master machine at an arbitrary time to make a request for synchronization; extracting, in said replica machine, a record of which a day of last update is later than a master differential extraction completion time, from the replica data as a replica differential; transferring the extracted replica differential to the master machine; extracting, in the master machine, a record of which a replica differential reflection time is later than a master differential extraction completion time, as a master differential from the master data with reference to records held by said replica machine which has made the request for synchronization, and updating the master differential extraction completion time to a current time; causing the replica differential to be reflected in the master data; transferring the master differential and the updated master differential extraction completion time to said replica machine; causing the master differential transferred from the master machine to be reflected in the replica data in said replica machine, and updating the master differential extraction completion time held by said replica machine to the transferred master differential extraction completion time; and cutting off the connection between said replica machine and the master machine.