Formal semantics of SQL queries

Formal semantics of SQL queries
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SQL 查询的形式语义

DOI：
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发表时间：
1991
期刊：
TODS
影响因子：
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通讯作者：
L. Sbattella
L. Sbattella
中科院分区：
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文献类型：
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作者：
Mauro Negri;G. Pelagatti;L. Sbattella

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SQL查询的语义是通过陈述一组规则来正式定义的，该规则确定了语法驱动的SQL查询对正式模型的翻译。目标模型，称为扩展的三个有价值的谓词微积分（E3VPC），主要基于一组众所周知的数学概念。允许将一般E3VPC表达式转换为规范形式的规则，该规则也可以使用传统的两值谓词计算进行操作；这样，完全解决了SQL查询的等效分析等问题。最后，显示了使用两值谓词演算的SQL查询等效性的推理，而无需照顾实际的SQL语义，这一事实可能会导致错误，并且分析了原因。
The semantics of SQL queries is formally defined by stating a set of rules that determine a syntax-driven translation of an SQL query to a formal model. The target model, called Extended Three Valued Predicate Calculus (E3VPC), is largely based on a set of well-known mathematical concepts. The rules which allow the transformation of a general E3VPC expression to a Canonical Form, which can be manipulated using traditional, two-valued predicate calculus are also given; in this way, problems like equivalence analysis of SQL queries are completely solved. Finally, the fact that reasoning about the equivalence of SQL queries using two-valued predicate calculus, without taking care of the real SQL semantics can lead to errors is shown, and the reasons for this are analyzed.