| T-SQL数据查询中的疑难分析 |
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| 引用本文： | 李久仲,石硕.T-SQL数据查询中的疑难分析[J].广东轻工职业技术学院学报,2006,5(3):8-10. |
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| 作者姓名： | 李久仲 石硕 |
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| 作者单位： | 广东轻工职业技术学院,计算机工程系,广东,广州,510300 |
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| 摘 要： | 带有全称量词命题与蕴含命题的数据查询是数据库应用系统中最实用的两类查询，但也是最难的两种数据查询。在这两类数据查询中，使用了多层嵌套子查询，致使学习者对查询语句的理解变得相当困难。本文从集合的角度分析了这两类查询难点所在，并通过实例阐明了实现这两类查询的编程思路，从而使学习者轻松理解和掌握这两类数据查询的方法。
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| 关 键 词： | 全称量词 蕴含运算 子查询 相关子查询 |
| 文章编号： | 1672-1950（2006）03-0008-03 |
| 收稿时间： | 2006-06-28 |
| 修稿时间： | 2006-06-28 |
Problems Analysis in Data Query of T-SQL |
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| LI Jiuzhong,SHI Suo.Problems Analysis in Data Query of T-SQL[J].Journal of Guangdong Industry Technical College,2006,5(3):8-10. |
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| Authors: | LI Jiuzhong SHI Suo |
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| Institution: | Computer Science Dept. Guangdong Industry Technical College , Guangzhou , 510300, China |
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| Abstract: | Data query for proposition with universal quantifier and data query for implication proposition are two categories of the most practical and difficult data queries. In the query of the two categories, the usage of nested Sub-queries makes it much difficult for the students to understand the query clause. This paper analyzes the difficulty of the two queries from the set point of view, and illuminates the programming thought of the two queries with examples and helps the students easily understand and have a good command of the method of the two queries. |
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| Keywords: | universal quantifier implication operation subquery correlated subquery |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
