The verso algebra or how to answer queries with fewer joins

摘要

The purpose of this paper is to demonstrate that, for the Verso model, nesting relations not only leads to a more natural data representation but also leads to more succinct and efficient data manipulation. In particular, a hightly expressive subclass of relational projection selection join expressions is exhibited, each element of this class being equivalent to a Verso selection/projection. The tableau technique is used to give a constructive characterization of these relational queries.