关于半连接查询的表达能力
数据库
2007-05-23 v2 计算机科学中的逻辑
摘要
半连接代数是通过将连接算子替换为半连接算子而获得的关系代数变体。我们提供了一个 Ehrenfeucht-Fraïssé 游戏，刻画半连接代数的区分能力。该游戏给出了一种证明查询不可在半连接代数中表达的方法。
引用
@article{arxiv.cs/0308014,
title = {On the expressive power of semijoin queries},
author = {Dirk Leinders and Jerzy Tyszkiewicz and Jan Van den Bussche},
journal= {arXiv preprint arXiv:cs/0308014},
year = {2007}
}
备注
9 pages, to appear in Information Processing Letters; added results that more clearly delineate the expressive power of SA, added a section that discusses the impact of order on the expressive power of SA, deemphasized the discussion on the relationship with GF