发明申请
- 专利标题: REDUNDANT VERSION INFORMATION IN HISTORY TABLE THAT ENABLES EFFICIENT SNAPSHOT QUERYING
- 专利标题(中): 历史表中的冗余版本信息使用有效的快照查询
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申请号: US12194540申请日: 2008-08-20
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公开(公告)号: US20080306907A1公开(公告)日: 2008-12-11
- 发明人: Dilip Kumar Biswal , Isaac Kam-Chak Cheng , Cecilia O. Chu , Donald Lee Clare , Louis S.W. Mau
- 申请人: Dilip Kumar Biswal , Isaac Kam-Chak Cheng , Cecilia O. Chu , Donald Lee Clare , Louis S.W. Mau
- 申请人地址: US NY Armonk
- 专利权人: International Business Machines Corporation
- 当前专利权人: International Business Machines Corporation
- 当前专利权人地址: US NY Armonk
- 主分类号: G06F7/06
- IPC分类号: G06F7/06 ; G06F17/30
摘要:
A system for efficient snapshot querying include: providing a first version value for each data in a history table, where the first version value indicates a beginning of a period in which the data is valid; providing at least a second version value for each data in the history table, where the second version value indicates an end of the period in which the data is valid; receiving a request for a version of a database; and retrieving the data with the first version value less than or equal to the requested version and the second version value greater than or equal to the requested version. By maintaining a history table with redundant version information, the system is able to provide efficient snapshot querying while also avoiding the overhead burden of conventional approaches. No aggregates, joins, or sub-queries are required to retrieve a snapshot.
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