Querying Heterogeneous Document Stores

NoSQL document stores offer support to store documents described using various structures. Hence, the user has to formulate queries using the possible representations of the desired information from different schemas. In this paper, we propose a novel approach that enables querying operators over a collection of documents with structural heterogeneity. Our work introduces an automatic query rewriting mechanism based on combinations of elementary operators: project, restrict and aggregate. We generate a custom dictionary that tracks all representations for attributes used in the documents. Finally, we discuss the results of our approach with a series of experiments.