关系代数的多态类型推断
Polymorphic type inference for the relational algebra
摘要：
给出了关系代数的多态性解释。我们介绍了一种专门为关系代数表达式调整的“类型公式”的形式主义，并提出了一种算法，用于计算给定表达式的“主要”类型。表达式的主类型是一个公式，它以清晰简洁的方式指定所有类型（属性集）到关系名称的赋值，在此条件下，给定的关系代数表达式是良好类型的，以及表达式在每个赋值下的输出类型。讨论的主题包括复杂性和多态表达能力。
英文摘要：
We give a polymorphic account of the relational algebra. We introduce a formalism of ``type formulas'' specifically tuned for relational algebra expressions, and present an algorithm that computes the ``principal'' type for a given expression. The principal type of an expression is a formula that specifies, in a clear and concise manner, all assignments of types (sets of attributes) to relation names, under which a given relational algebra expression is well-typed, as well as the output type that expression will have under each of these assignments. Topics discussed include complexity and polymorphic expressive power.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
