Preface -- Acknowledgments -- Queries and Views -- Query Containment and Equivalence -- Finding Equivalent Rewritings -- Maximally Contained Rewritings (MCRs) -- Answering Queries in Presence of Dependencies -- Answering Queries in Data Exchange -- Answering Queries Using Views -- Bibliographical Notes -- Conclusion -- Bibliography -- Authors' Biographies.

The topic of using views to answer queries has been popular for a few decades now, as it cuts across domains such as query optimization, information integration, data warehousing, website design, and, recently, database-as-a-service and data placement in cloud systems. This book assembles foundational work on answering queries using views in a self-contained manner, with an effort to choose material that constitutes the backbone of the research. It presents efficient algorithms and covers the following problems: query containment; rewriting queries using views in various logical languages; equivalent rewritings and maximally contained rewritings; and computing certain answers in the data-integration and data-exchange settings. Query languages that are considered are fragments of SQL, in particular, select-project-join queries, also called conjunctive queries (with or without arithmetic comparisons or negation), and aggregate SQL queries.