Declarative Features for Deductive Databases

演绎数据库提供了一个声明性的框架， 用于编写查询的一阶逻辑。 在数据库中搜索 定义查询的答案，但不指示如何回答 查询. 通过允许递归，演绎数据库产生更高的 比传统的关系数据库更强大的表达能力。 两 在这个项目中解决的主要问题是语义和 优化.本研究主要研究演绎语义 使用聚合运算符（如“minimum”）扩展的数据库 “和”。''将这样的语义扩展到具有 二阶结构也被考虑。 该项目 评估二阶特征如何有效地 现在的关系数据库中。 优化 技术的演绎数据库与聚集，既新的 技术和现有策略的扩展也 追究该项目将为基础 关于如何提供声明性功能的知识，例如 聚合和二阶结构，在演绎 数据库。

Deductive databases provide a declarative framework based on first-order logic for writing queries. Entries in the database define the answer to a query without indicating how to answer the query. By allowing recursion, deductive databases yield higher expressive power than classical relational databases. The two main problems addressed in this project are semantics and optimization. This research studies semantics for deductive databases extended with aggregate operators such as ``minimum'' and ``sum.'' Extensions of such semantics to programs with second-order constructs are also considered. The project is assessing how effectively second-order features can be incorporated into present-day relational databases. Optimization techniques for deductive databases with aggregates, both new techniques and extensions of existing strategies are also be investigated. This project will contribute fundamental knowledge about how to provide declarative features, such as aggregation and second-order constructs, within deductive databases.