Similarity joins have been studied as key operations in multiple application domains, e.g., record linkage, data cleaning, multimedia and video applications, and phenomena detection on sensor networks. Multiple similarity join algorithms and implementation techniques have been proposed. They range from out-of-database approaches for only in-memory and external memory data to techniques that make use of standard database operators to answer similarity joins. Unfortunately, there has not been much study on the role and implementation of similarity joins as database physical operators. In this paper, we focus on the study of similarity joins as first-class database operators. We present the definition of several similarity join operators and study the way they interact among themselves, with other standard database operators, and with other previously proposed similarity-aware operators. In particular, we present multiple transformation rules that enable similarity query optimization thro...
Mohamed H. Ali, Walid G. Aref, Yasin N. Silva