| 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: |
|
| The Primary Research of Null Value Processing on Knowledge Base Systems |
|
Yuan Bingyan1, Hua Wei2
|
| (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 |
