Equivalence of datalog queries is undecidable
Journal of Logic Programming
Undecidable optimization problems for database logic programs
Journal of the ACM (JACM)
Equivalences Among Relational Expressions with the Union and Difference Operators
Journal of the ACM (JACM)
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Data integration under integrity constraints
Information Systems - Special issue: The 14th international conference on advanced information systems engineering (CAiSE*02)
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
Data exchange: getting to the core
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2003
XML data exchange: consistency and query answering
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Schema mappings, data exchange, and metadata management
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Computing cores for data exchange: new algorithms and practical solutions
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Clio grows up: from research prototype to industrial tool
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Composing schema mappings: Second-order dependencies to the rescue
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Data exchange: computing cores in polynomial time
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Composition of mappings given by embedded dependencies
ACM Transactions on Database Systems (TODS)
Model management 2.0: manipulating richer mappings
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Compiling mappings to bridge applications and databases
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Quasi-inverses of schema mappings
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Composing mappings among data sources
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Structural characterizations of schema-mapping languages
Proceedings of the 12th International Conference on Database Theory
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Clio: Schema Mapping Creation and Data Exchange
Conceptual Modeling: Foundations and Applications
Laconic schema mappings: computing the core with SQL queries
Proceedings of the VLDB Endowment
Inverting schema mappings: bridging the gap between theory and practice
Proceedings of the VLDB Endowment
Normalization and optimization of schema mappings
Proceedings of the VLDB Endowment
Composition with target constraints
Proceedings of the 13th International Conference on Database Theory
Characterizing schema mappings via data examples
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Composition and inversion of schema mappings
ACM SIGMOD Record
Logic and data exchange: which solutions are "good" solutions?
LOFT'08 Proceedings of the 8th international conference on Logic and the foundations of game and decision theory
Scalable data exchange with functional dependencies
Proceedings of the VLDB Endowment
Relaxed notions of schema mapping equivalence revisited
Proceedings of the 14th International Conference on Database Theory
Proceedings of the 14th International Conference on Database Theory
ACM Transactions on Database Systems (TODS)
Normalization and optimization of schema mappings
The VLDB Journal — The International Journal on Very Large Data Bases
Designing and refining schema mappings via data examples
Proceedings of the 2011 ACM SIGMOD International Conference on Management of data
Characterizing schema mappings via data examples
ACM Transactions on Database Systems (TODS)
Tableaux-based optimization of schema mappings for data integration
Journal of Intelligent Information Systems
Local transformations and conjunctive-query equivalence
PODS '12 Proceedings of the 31st symposium on Principles of Database Systems
Core schema mappings: Scalable core computations in data exchange
Information Systems
Representation systems for data exchange
Proceedings of the 15th International Conference on Database Theory
Query language-based inverses of schema mappings: semantics, computation, and closure properties
The VLDB Journal — The International Journal on Very Large Data Bases
A sound and complete chase procedure for constrained tuple-generating dependencies
Journal of Intelligent Information Systems
On simplification of schema mappings
Journal of Computer and System Sciences
The language of plain SO-tgds: Composition, inversion and structural properties
Journal of Computer and System Sciences
Exchanging OWL 2 QL knowledge bases
IJCAI'13 Proceedings of the Twenty-Third international joint conference on Artificial Intelligence
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A schema mapping is a high-level specification that describes the relationship between two database schemas. As schema mappings constitute the essential building blocks of data exchange and data integration, an extensive investigation of the foundations of schema mappings has been carried out in recent years. Even though several different aspects of schema mappings have been explored in considerable depth, the study of schema-mapping optimization remains largely uncharted territory to date. In this paper, we lay the foundation for the development of a theory of schema-mapping optimization. Since schema mappings are constructs that live at the logical level of information integration systems, the first step is to introduce concepts and to develop techniques for transforming schema mappings to "equivalent" ones that are more manageable from the standpoint of data exchange or of some other data interoperability task. In turn, this has to start by introducing and studying suitable notions of "equivalence" between schema mappings. To this effect, we introduce the concept of data-exchange equivalence and the concept of conjunctive-query equivalence. These two concepts of equivalence are natural relaxations of the classical notion of logical equivalence; the first captures indistinguishability for data-exchange purposes, while the second captures indistinguishability for conjunctive-query-answering purposes. Moreover, they coincide with logical equivalence on schema mappings specified by source-to-target tuple-generating dependencies (s-t tgds), but differ on richer classes of dependencies, such as second-order tuple-generating dependencies (SO tgds) and sets of s-t tgds and target tuple-generating dependencies (target tgds). After exploring the basic properties of these three notions of equivalence between schema mappings, we focus on the following question: under what conditions is a schema mapping conjunctive-query equivalent to a schema mapping specified by a finite set of s-t tgds? We answer this question by obtaining complete characterizations for schema mappings that are specified by an SO tgd and for schema mappings that are specified by a finite set of s-t tgds and target tgds, and have terminating chase. These characterizations involve boundedness properties of the cores of universal solutions.