| SQL类查询语句的基本结构及其到关系代数表达式的转换 |
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| 引用本文： | 徐国定. SQL类查询语句的基本结构及其到关系代数表达式的转换[J]. 华东师范大学学报(自然科学版), 1985, 0(3) |
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| 作者姓名： | 徐国定 |
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| 作者单位： | 华东师范大学计算机科学系 |
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| 摘 要： | 本文分析了SQL类查询语句的基本结构,指出任何一个嵌套结构的SQL类语句都可以由四种基本嵌套类型组成.在分析基础上,提出了将SQL类查询语句转换成关系代数表达式的算法.
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| 关 键 词： | 查询语言 关系完备性 关系代数 |
The Basic Structure of SQL-like Query and Its Transformation into Algebraic Expression |
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| XU GUODING. The Basic Structure of SQL-like Query and Its Transformation into Algebraic Expression[J]. Journal of East China Normal University(Natural Science), 1985, 0(3) |
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| Authors: | XU GUODING |
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| Affiliation: | Department of Computer Sciences |
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| Abstract: | The structure of SQL-like nested queries is examined.It is shown that any SQL-like nested query can be decomposed into four basic nested types.An algorithm which converts an SQL-like query into an algebraic expression is given. |
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| Keywords: | query language relational completeness relational algebra. |
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