To accurately detect an update competition by judging to be an update composition, unless the latest update serial number of received data matches with one of update serial numbers except the latest update serial number of object data.
A data reception part 112 of a data base system 109 on a secondary replica side receives update data and reference relation data transferred from a 1st computer and an update conflict decision part 115 decides an update conflict between the receive data and secondary replica data 110 corresponding to the receive data. Namely, the update serial number in the update serial number history of the data is compared with the update serial number in the update serial number history of object data to be updated and reflected, and it is judged to be an update competion unless the latest update serial number of the object data matches one of the update serial numbers except the latest update serial number of the received data and the latest update serial number of the received data matches one of the update serial numbers except the latest update serial number of the object data.
WAKAYAMA SATORU
MARUYAMA TAKEO
TANAKA HITOSHI
NISHIKAWA NORIFUMI
TAKATANI HIDEYUKI
HITACHI KIDEN KOGYO KK
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