— The database research community has recently recognized the usefulness of skyline query. As an extension of existing database operator, the skyline query is valuable for multi-criteria decision making. However, current research tends to assume that the skyline operator is applied to one table which is not true for many applications on web databases. In web databases, tables are distributed in different sites, and a skyline query may involve attributes of multiple tables. In this paper, we address the problem of processing skyline queries on multiple tables in a distributed environment. We call the new operator skyline-join, as it is a hybrid of skyline and join operations. We propose two efficient approaches to process skyline-join queries which can significantly reduce the communication cost and processing time. Experiments are conducted and results show that our approaches are efficient for distributed skyline-join queries.
Dalie Sun, Sai Wu, Jianzhong Li, Anthony K. H. Tun