Incorporating Data Concerns into Query Languages for Data Services

Abstract

More and more organizations provide their data on the web via data services - also referred to as Data as a Service (DaaS). Data services combine the strength of database systems and query languages on the one hand with the benefits of service-oriented architecture on the other hand. Data services are increasingly used for data integration. The data provided via data services is often associated with data concerns like privacy, licensing, pricing, quality of data, etc. Hence, data integration tools not only have to mitigate the heterogeneity in data formats and query languages. In addition, also the various data concerns should be preserved when data is published and utilized. Moreover, data service selection and data selection should be based on these data concerns. Current Data Integration systems using data services lack the ability to preserve data concerns while querying multiple services in an integrated environment. In this paper, we design a new querying system which takes data concerns into account. To this end we discuss several models of data concern aware querying and select the best suited one for our system. We describe a querying system where data concern awareness is integrated directly into the XQuery language. We also report on an implementation and experimental evaluation of this system.