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11. 发明授权

US07363299B2 Computing probabilistic answers to queries 失效
标题翻译：计算查询的概率答案
公开(公告)号：US07363299B2
公开(公告)日：2008-04-22
申请号：US11281983
申请日：2005-11-17
申请人： Nilesh Dalvi , Dan Suciu
发明人： Nilesh Dalvi , Dan Suciu
IPC分类号： G06F17/30
CPC分类号： G06F17/30542 , Y10S707/99933
摘要： A system that supports arbitrarily complex SQL queries with “uncertain” predicates. The query semantics are based on a probabilistic model and the results are ranked, much like in Information Retrieval, based upon their probability. An optimization algorithm is employed that can efficiently compute most queries. The algorithm attempts to determine whether a proposed plan is a safe plan that can be used for correctly evaluating the query. Operators such as the project operator in the proposed plan are evaluated to determine if they are safe. If so, the proposed plan is safe and will produce correct answers in a result. Due to the data complexity of some queries, a safe plan may not exist for a query. For these queries, either a “least unsafe plan,” or a Monte-Carlo simulation algorithm can be employed to produce a result with answers that have an acceptable error.
摘要翻译：支持任意复杂的SQL查询与“不确定”谓词的系统。查询语义基于概率模型，结果被排序，就像在信息检索中一样，基于它们的概率。采用可以有效地计算大多数查询的优化算法。该算法尝试确定提出的计划是否是可用于正确评估查询的安全计划。对拟议计划中的项目经营者等运营商进行评估，以确定其是否安全。如果是这样，提出的计划是安全的，并将产生正确的答案。由于某些查询的数据复杂性，查询可能不存在安全计划。对于这些查询，可以采用“最不安全的计划”或蒙特卡罗模拟算法来产生具有可接受错误的答案的结果。

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