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. This second edition includes two new chapters that refer to tree-like data and respective query languages. Chapter 8 presents the data model for XML documents and the XPath query language, and Chapter 9 provides a theoretical presentation of tree-like data model and query language where the tuples of a relation share a tree-structured schema for that relation and the query language is a dialect of SQL with evaluation techniques appropriately modified to fit the richer schema.

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.

This book constitutes the refereed proceedings of the 8th International Conference on Flexible Query Answering Systems, FQAS 2009, held in Roskilde, Denmark, in October 2009. The 57 papers included in this volume were carefully reviewed and selected from 90 submissions. They are structured in topical sections on database management, information retrieval, extraction and mining, ontologies and semantic web, intelligent information extraction from texts, advances in fuzzy querying, personalization, preferences, context and recommendation, and Web as a stream.

This book constitutes the refereed proceedings of the 10th International Conference on Extending Database Technology, EDBT 2006, held in Munich, Germany, in March 2006. The 60 revised research papers presented together with eight industrial application papers, 20 software demos, and three invited contributions were carefully reviewed and selected from 352 submissions. The papers are organized in topical sections.

This book constitutes the refereed proceedings of the 13th East European Conference on Advances in Databases and Information Systems, ADBIS 2009, held in Riga, Latvia, on September 7-10, 2009. The 25 revised papers were carefully reviewed and selected from 93 submissions. Topically, the papers span a wide spectrum of the database and information system. Topics are ranging from query processing and optimization via query languages, design methods, data integration, indexing and caching to business processes, data mining, and application oriented topics like XML and data on the Web.

This book constitutes the thoroughly refereed post-workshop proceedings of the Third International Workshop on Semantics in Data and Knolwedge Bases, SDKB 2008, held in Nantes, France, on March 29, 2008. The 6 revised full papers presented together with 4 invited papers and a survey on the state of the art in the field, were carefully reviewed and selected for inclusion in the book. The SDKB workshop presented original contributions demonstrating the use of logic, discrete mathematics, combinatorics, domain theory and other mathematical theories of semantics for database and knowledge bases, computational linguistics and semiotics, and information and knowledge-based systems.

The Eighth International Conference on Extending Database Technology, EDBT 2002, was held in Prague, Czech Republic, March 25–27, 2002. It marks the 50th anniversary of Charles University’s Faculty of Mathematics and Physics and is the most recent in a series of conferences dedicated to the dissemination and exchange of the latest advances in data management. Previous conferences occurred in Konstanz, Valencia, Avignon, Cambridge, Vienna, and Venice. The topical theme of this year’s conference is Data Management in the New Millennium, which encourages the community to see beyond the management of massive databases by conventional database management systems and to extend database technology to support new services and application areas. The intention is to spur greater interest in more integrated solutions to user problems, which often implies the consideration of data management issues in entire information systems infrastructures. There is data (almost) everywhere, and data access is needed (almost) always and everywhere. New technologies, services, and app- cations that involve the broader notion of data management are emerging more rapidly than ever, and the database community has much to o?er. The call for papers attracted numerous submissions, including 207 research papers, which is a new record for EDBT. The program committee selected 36 research papers, 6 industrial and applications papers, 13 software demos, and 6 tutorials for presentation at the conference. In addition, the conference program includes three keynote speeches, by Jari Ahola, Ian Horrocks, and Hans-J ̈org Schek, and a panel.

The Internet and the World Wide Web (WWW) are becoming more and more important in our highly interconnected world as more and more data and information is made available for online access. Many individuals and governmental, commercial, cultural, and scientific organizations increasingly depend on information sources that can be accessed and queried over the Web. For example, accessing flight schedules or retrieving stock information has become common practice in todays world. When accessing this data, many people assume that the information accessed is accurate and that the data source can be accessed reliably. These two examples clearly demonstrate that not only the information content is important, the information about the quality of the data becomes an even more crucial and critical aspect for individuals and organizations when they make plans or take decisions based on the results of their queries. More precisely, having access to information of known quality becomes critical for the well-being and indeed for the functioning of modern industrialized societies. Surprisingly, despite the urgent need for clear concepts and techniques to judge and value quality and for technology to use such (meta) information, very few scientific results are known and available. Few approaches are known to use quality measures for accessing and querying information over the Web. Only a limited number of products on the IT market address this burning problem.

The two-volume set LNAI 6591 and LNCS 6592 constitutes the refereed proceedings of the Third International Conference on Intelligent Information and Database Systems, ACIIDS 2011, held in Daegu, Korea, in April 2011. The 110 revised papers presented together with 2 keynote speeches were carefully reviewed and selected from 310 submissions. The papers are thematically divided into two volumes; they cover the following topics: intelligent database systems, data warehouses and data mining, natural language processing and computational linguistics, semantic Web, social networks and recommendation systems, technologies for intelligent information systems, collaborative systems and applications, e-business and e-commerce systems, e-learning systems, information modeling and requirements engineering, information retrieval systems, intelligent agents and multi-agent systems, intelligent information systems, intelligent internet systems, intelligent optimization techniques, object-relational DBMS, ontologies and knowledge sharing, semi-structured and XML database systems, unified modeling language and unified processes, Web services and semantic Web, computer networks and communication systems.

This book constitutes the refereed proceedings of the 4th International Conference on Web-Age Information Management, WAIM 2003, held in Chengdu, China in August 2003. The 30 revised full papers and 16 revised short papers presented together with 2 invited contributions were carefully reviewed and selected from 258 submissions. The papers are organized in topical sections on Web; XML; text management; data mining; bioinformatics; peer-to-peer systems; service networks; time series, similarity, and ontologies; information filtering; queries and optimization; multimedia and views; and systems demonstrations.