Answering Queries Using Views

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.

Table of Contents

Chapter 1. Queries and Views
Chapter 2. Query Containment and Equivalence
Chapter 3. Finding Equivalent Rewritings
Chapter 4. Maximally Contained Rewritings (MCRs)
Chapter 5. Answering Queries in Presence of Dependencies
Chapter 6. Answering Queries in Data Exchange
Chapter 7. Answering Queries Using Views
Chapter 8. Bibliographical Notes
Chapter 9. Conclusion