Method of comparing replicated databases using checksum information
US5974574A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/1451
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of checking a large and/or replicated databases includes forming a position sensitive checksum for each entry of the database to be used in the check. The checksums are then exclusive Ored with one another to form a first database checksum. Periodically, the checksums are again created from each of the entries of the check and a second database checksum formed and compared to the first for a match that indicate checked entries of the database have not changed. In another embodiment, a modification to one of the check entries may be provided, accompanied by a master checksum indicative of what the first checksum should be after the entry is modified. The database entry is modified, and a position checksum value for the entry as modified is created. The checksum value for the modified entry, and for the entry before the modification, are exclusive OR with the first checksum value, and that result compared with the master checksum to ensure that the modification was properly made and that the database remains credible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.