Database Repairing And Consistent Query Answering

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Database Repairing And Consistent Query Answering

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Author : Leopoldo Bertossi
language : en
Publisher: Springer Nature
Release Date : 2022-05-31

Database Repairing And Consistent Query Answering written by Leopoldo Bertossi and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-05-31 with Computers categories.

Integrity constraints are semantic conditions that a database should satisfy in order to be an appropriate model of external reality. In practice, and for many reasons, a database may not satisfy those integrity constraints, and for that reason it is said to be inconsistent. However, and most likely, a large portion of the database is still semantically correct, in a sense that has to be made precise. After having provided a formal characterization of consistent data in an inconsistent database, the natural problem emerges of extracting that semantically correct data, as query answers. The consistent data in an inconsistent database is usually characterized as the data that persists across all the database instances that are consistent and minimally differ from the inconsistent instance. Those are the so-called repairs of the database. In particular, the consistent answers to a query posed to the inconsistent database are those answers that can be simultaneously obtained from all the database repairs. As expected, the notion of repair requires an adequate notion of distance that allows for the comparison of databases with respect to how much they differ from the inconsistent instance. On this basis, the minimality condition on repairs can be properly formulated. In this monograph we present and discuss these fundamental concepts, different repair semantics, algorithms for computing consistent answers to queries, and also complexity-theoretic results related to the computation of repairs and doing consistent query answering. Table of Contents: Introduction / The Notions of Repair and Consistent Answer / Tractable CQA and Query Rewriting / Logically Specifying Repairs / Decision Problems in CQA: Complexity and Algorithms / Repairs and Data Cleaning

Optimizing Repair Programs For Consistent Query Answering In Databases

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Author : Monica Caniupan
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2011-05

Optimizing Repair Programs For Consistent Query Answering In Databases written by Monica Caniupan and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-05 with categories.

Databases may not always satisfy their integrity constraints (ICs). However, in most cases an important part of the data is still consistent with the ICs, and can still be retrieved through queries posed to the database. Consistent query answers are characterized as answers obtained from every minimally repaired and consistent version of the database. Database repairs can be specied as stable models of disjunctive logic programs. Consistent Query Answering (CQA) for first-order queries is translated into cautious reasoning under the stable models semantics. Using logic programs in a straightforward manner is usually inefficient. We develop optimized techniques to evaluate queries over inconsistent databases by using logic programs. We optimize the structure of programs, model computation, and evaluation of queries from them. Moreover, we propose the use of the well-founded semantics (WFS) as an alternative way to obtain consistent answers. The WFS has lower data complexity than the stable models semantics. We also extend the use of logic programs for retrieving consistent answers to aggregate queries, and we develop a repair semantics for Data Warehouses.

Data Cleaning

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Author : Ihab F. Ilyas
language : en
Publisher: Morgan & Claypool
Release Date : 2019-06-18

Data Cleaning written by Ihab F. Ilyas and has been published by Morgan & Claypool this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-06-18 with Computers categories.

This is an overview of the end-to-end data cleaning process. Data quality is one of the most important problems in data management, since dirty data often leads to inaccurate data analytics results and incorrect business decisions. Poor data across businesses and the U.S. government are reported to cost trillions of dollars a year. Multiple surveys show that dirty data is the most common barrier faced by data scientists. Not surprisingly, developing effective and efficient data cleaning solutions is challenging and is rife with deep theoretical and engineering problems. This book is about data cleaning, which is used to refer to all kinds of tasks and activities to detect and repair errors in the data. Rather than focus on a particular data cleaning task, this book describes various error detection and repair methods, and attempts to anchor these proposals with multiple taxonomies and views. Specifically, it covers four of the most common and important data cleaning tasks, namely, outlier detection, data transformation, error repair (including imputing missing values), and data deduplication. Furthermore, due to the increasing popularity and applicability of machine learning techniques, it includes a chapter that specifically explores how machine learning techniques are used for data cleaning, and how data cleaning is used to improve machine learning models. This book is intended to serve as a useful reference for researchers and practitioners who are interested in the area of data quality and data cleaning. It can also be used as a textbook for a graduate course. Although we aim at covering state-of-the-art algorithms and techniques, we recognize that data cleaning is still an active field of research and therefore provide future directions of research whenever appropriate.

Flexible Query Answering Systems

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Author : Henrik Legind Larsen
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-05-30

Flexible Query Answering Systems written by Henrik Legind Larsen and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-05-30 with Computers categories.

This book constitutes the refereed proceeding of the 7th International Conference on Flexible Query Answering Systems, FQAS 2006, held in Milan, Italy in June 2006. The 60 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on flexibility in database management and quering, vagueness and uncertainty in XML quering and retrieval, information retrieval and filtering, multimedia information access, user modeling and personalization, knowledge and data extraction, intelligent information extraction from text, and knowledge representation and reasoning.

Flexible Query Answering Systems

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Author : Troels Andreasen
language : en
Publisher: Springer Nature
Release Date : 2021-09-15

Flexible Query Answering Systems written by Troels Andreasen and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-09-15 with Computers categories.

This book constitutes the refereed proceedings of the 14th International Conference on Flexible Query Answering Systems, FQAS 2021, held virtually and in Bratislava, Slovakia, in September 2021. The 16 full papers and 1 perspective papers presented were carefully reviewed and selected from 17 submissions. They are organized in the following topical sections: model-based flexible query answering approaches and data-driven approaches.

Repairing And Querying Databases Under Aggregate Constraints

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Author : Sergio Flesca
language : en
Publisher: Springer Science & Business Media
Release Date : 2011-10-20

Repairing And Querying Databases Under Aggregate Constraints written by Sergio Flesca and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-10-20 with Computers categories.

Research has deeply investigated several issues related to the use of integrity constraints on relational databases. In particular, a great deal of attention has been devoted to the problem of extracting "reliable" information from databases containing pieces of information inconsistent with regard to some integrity constraints. In this manuscript, the problem of extracting consistent information from relational databases violating integrity constraints on numerical data is addressed. Aggregate constraints defined as linear inequalities on aggregate-sum queries on input data are considered. The notion of repair as consistent set of updates at attribute-value level is exploited, and the characterization of several data-complexity issues related to repairing data and computing consistent query answers is provided. Moreover, a method for computing “reasonable” repairs of inconsistent numerical databases is introduced, for a restricted but expressive class of aggregate constraints. An extension of this method for dealing with the data repairing problem in the presence of weak aggregate constraints which are expected to be satisfied, but not required to, is presented. Furthermore, a technique for computing consistent answers of aggregate queries in the presence of a wide form of aggregate constraints is provided. Finally, extensions of the framework as well as several open problems are discussed.

Mysql Reference Manual

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Author : Michael Widenius
language : en
Publisher: "O'Reilly Media, Inc."
Release Date : 2002

Mysql Reference Manual written by Michael Widenius and has been published by "O'Reilly Media, Inc." this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Computers categories.

This comprehensive reference guide offers useful pointers for advanced use of SQL and describes the bugs and workarounds involved in compiling MySQL for every system.

Scalable Uncertainty Management

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Author : Davide Ciucci
language : en
Publisher: Springer
Release Date : 2018-09-24

Scalable Uncertainty Management written by Davide Ciucci and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-09-24 with Computers categories.

This book constitutes the refereed proceedings of the 12th International Conference on Scalable Uncertainty Management, SUM 2018, which was held in Milan, Italy, in October 2018. The 23 full, 6 short papers and 2 tutorials presented in this volume were carefully reviewed and selected from 37 submissions. The conference is dedicated to the management of large amounts of complex, uncertain, incomplete, or inconsistent information. New approaches have been developed on imprecise probabilities, fuzzy set theory, rough set theory, ordinal uncertainty representations, or even purely qualitative models.

Theory And Applications Of Satisfiability Testing Sat 2019

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Author : Mikoláš Janota
language : en
Publisher: Springer
Release Date : 2019-06-28

Theory And Applications Of Satisfiability Testing Sat 2019 written by Mikoláš Janota and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-06-28 with Computers categories.

This book constitutes the refereed proceedings of the 22nd International Conference on Theory and Applications of Satisfiability Testing, SAT 2019, held in Lisbon, Portugal, UK, in July 2019. The 19 revised full papers presented together with 7 short papers were carefully reviewed and selected from 64 submissions. The papers address different aspects of SAT interpreted in a broad sense, including (but not restricted to) theoretical advances (such as exact algorithms, proof complexity, and other complexity issues), practical search algorithms, knowledge compilation, implementation-level details of SAT solvers and SAT-based systems, problem encodings and reformulations, applications (including both novel application domains and improvements to existing approaches), as well as case studies and reports on findings based on rigorous experimentation.

New Trends In Intelligent Software Methodologies Tools And Techniques

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Author : H. Fujita
language : en
Publisher: IOS Press
Release Date : 2021-09-28

New Trends In Intelligent Software Methodologies Tools And Techniques written by H. Fujita and has been published by IOS Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-09-28 with Computers categories.

The integration of AI with software is an essential enabler for science and the new economy, creating new markets and opportunities for a more reliable, flexible and robust society. Current software methodologies, tools and techniques often fall short of expectations, however, and much software remains insufficiently robust and reliable for a constantly changing and evolving market. This book presents 54 papers delivered at the 20th edition of the International Conference on New Trends in Intelligent Software Methodology Tools, and Techniques (SoMeT_21), held in Cancun, Mexico, from 21–23 September 2021. The aim of the conference was to capture the essence of a new state-of-the-art in software science and its supporting technology and to identify the challenges that such a technology will need to master, and this book explores the new trends and theories illuminating the direction of development in this field as it heads towards a transformation in the role of software and science integration in tomorrow’s global information society. The 54 revised papers were selected for publication by means of a rigorous review process involving 3 or 4 reviewers for each paper, followed by selection by the SoMeT_21 international reviewing committee. The book is divided into 9 chapters, classified by paper topic and relevance to the chapter theme. Covering topics ranging from research practices, techniques and methodologies to proposing and reporting on the solutions required by global business, the book offers an opportunity for the software science community to consider where they are today and where they are headed in the future.