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| 引用本文： |
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袁冰艳,华为.知识库中的空值初探[J].广西科学院学报,1996,(2):31-35. [点击复制]
- Yuan Bingyan,Hua Wei.The Primary Research of Null Value Processing on Knowledge Base Systems[J].Journal of Guangxi Academy of Sciences,1996,(2):31-35. [点击复制]
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| 知识库中的空值初探 |
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袁冰艳1, 华为2
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| (1.广西卫生管理干部学院, 南宁 530021;2.上海市电话局设计所, 上海 200092) |
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| 摘要: |
| 分析了空值环境下的三种类型的查询策略,以及Datalog查询求值的Semi-Naive算法,给出了一个从子目标关系空值特性导出头关系空值特性的一种方法,使改进后的Semi-Naive算法能在带有空值的EDB数据库中对Datalog查询进行正确求值。 |
| 关键词: 知识库 空值 Datalog查询 |
| DOI： |
| 投稿时间：1996-03-25 |
| 基金项目: |
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| The Primary Research of Null Value Processing on Knowledge Base Systems |
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Yuan Bingyan1, Hua Wei2
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| (1.Guangxi Health Manage Cadre Institute, Nanning, 530021;2.Shanghai Design Institute of Telephone Exchange, Shanghai, 200092) |
| Abstract: |
| By analysing the three kinds of query strategies under null values environment and the Semi-Naive algorithm of Datalog query Evaluation. A method to obtain the null value features of IDB's attributs from that of EDB's is given for the Semi-Naive algorithm to correctly complete the computation in Datalog query of EDB with null values. |
| Key words: knowledge bases null values Datalog queries |
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