发明授权
US07739262B2 Enforcing currency and consistency constraints in database query processing
有权
在数据库查询处理中强制执行货币和一致性限制
- 专利标题: Enforcing currency and consistency constraints in database query processing
- 专利标题(中): 在数据库查询处理中强制执行货币和一致性限制
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申请号: US10805083申请日: 2004-03-19
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公开(公告)号: US07739262B2公开(公告)日: 2010-06-15
- 发明人: Per-Åke Larson , Jonathan David Goldstein , Raghu Ramakrishnan , Hongfei Guo
- 申请人: Per-Åke Larson , Jonathan David Goldstein , Raghu Ramakrishnan , Hongfei Guo
- 申请人地址: US WA Redmond
- 专利权人: Microsoft Corporation
- 当前专利权人: Microsoft Corporation
- 当前专利权人地址: US WA Redmond
- 主分类号: G06F17/30
- IPC分类号: G06F17/30
摘要:
Currency and consistency requirements are specified as part of a query against a database that may contain replicated data that is updated asynchronously and therefore may not be completely up to date. The database system constructs query execution plans that include an input selection operator that verifies the currency of a replica and selects a subplan using the replica for execution only when the replica meets the query's currency constraints. It checks possible query execution plans at construction time against the query's consistency constraints and any plans that may produce a result not meeting the consistency constraints are rejected. In this way, the query result is guaranteed to satisfy the query's currency and consistency requirements.