On tree-based techniques for query evaluation
Håkan Jakobsson · 1992
We discuss a technique for query evaluation based on storing intermediary results as trees and study two applications. We first consider the problem of computing the transitive closure of a graph for a specific set of source nodes. Algorithms for this problem can be directly applied to many nonrecursive queries as well. We give a new algorithm and show that it is superior to several previous algorithms. We then consider Warshall's transitive closure algorithm. This algorithm is not O(n e), but we show that by using trees instead flat representations of intermediary results, we can derive a new version of the algorithm with an O(n e> upper bound.