Patent ID: 8751445

Claim:
A method of synchronizing data in response to a retrieval request between a first database and at least one second database each holding at least a portion of data included in the first database using an electronic computing device, the method comprising: causing the electronic computing device, in response to issuing the retrieval request to the second database, to extract, from the first database, differential data corresponding with the retrieval request between a first data set in the first database and a second data set in the second database as a retrieval target of the retrieval request, wherein the retrieval request includes a current retrieval request and a future retrieval request, wherein the future retrieval request is configured for issuance after the current retrieval request; and updating the second data set by applying only the differential data corresponding with the retrieval request to the second database and by recording a time of updating the second data set, wherein the updated second data set is the retrieval target of the retrieval request, wherein the differential data corresponding with the retrieval request represents only a portion of data out of all possible data sets that differ between the first database and the second database, and wherein the differential data indicates a difference between the second data set at a time of issue of a past retrieval request wherein the time of issue of the past retrieval issued before the retrieval request, and the second data set at the time of issue of the retrieval request.