Chromatically optimal rigid graphs
Journal of Combinatorial Theory Series B
Discrete Mathematics - Algebraic graph theory; a volume dedicated to Gert Sabidussi
An introduction to computational learning theory
An introduction to computational learning theory
On bounded treewidth duality of graphs
Journal of Graph Theory
A shorter model theory
Horn clauses and database dependencies
Journal of the ACM (JACM)
Data-driven understanding and refinement of schema mappings
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
Clio: a semi-automatic tool for schema mapping
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
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
Undirected ST-connectivity in log-space
Proceedings of the thirty-seventh annual ACM symposium on Theory of computing
Schema mappings, data exchange, and metadata management
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
Short Answers to Exponentially Long Questions: Extremal Aspects of Homomorphism Duality
SIAM Journal on Discrete Mathematics
Debugging schema mappings with routes
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
ACM Transactions on Database Systems (TODS)
European Journal of Combinatorics
On the complexity of deriving schema mappings from database instances
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Towards a theory of schema-mapping optimization
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
STBenchmark: towards a benchmark for mapping systems
Proceedings of the VLDB Endowment
Structural characterizations of schema-mapping languages
Proceedings of the 12th International Conference on Database Theory
Muse: Mapping Understanding and deSign by Example
ICDE '08 Proceedings of the 2008 IEEE 24th International Conference on Data Engineering
Generating example data for dataflow programs
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Schema mapping discovery from data instances
Journal of the ACM (JACM)
Characterizing schema mappings via data examples
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Database constraints and homomorphism dualities
CP'10 Proceedings of the 16th international conference on Principles and practice of constraint programming
Designing and refining schema mappings via data examples
Proceedings of the 2011 ACM SIGMOD International Conference on Management of data
Schema mappings and data examples
Proceedings of the 16th International Conference on Extending Database Technology
Ontology-based data access: a study through disjunctive datalog, CSP, and MMSNP
Proceedings of the 32nd symposium on Principles of database systems
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Schema mappings are high-level specifications that describe the relationship between two database schemas; they are considered to be the essential building blocks in data exchange and data integration, and have been the object of extensive research investigations. Since in real-life applications schema mappings can be quite complex, it is important to develop methods and tools for understanding, explaining, and refining schema mappings. A promising approach to this effect is to use “good” data examples that illustrate the schema mapping at hand. We develop a foundation for the systematic investigation of data examples and obtain a number of results on both the capabilities and the limitations of data examples in explaining and understanding schema mappings. We focus on schema mappings specified by source-to-target tuple generating dependencies (s-t tgds) and investigate the following problem: which classes of s-t tgds can be “uniquely characterized” by a finite set of data examples? Our investigation begins by considering finite sets of positive and negative examples, which are arguably the most natural choice of data examples. However, we show that they are not powerful enough to yield interesting unique characterizations. We then consider finite sets of universal examples, where a universal example is a pair consisting of a source instance and a universal solution for that source instance. We first show that unique characterizations via universal examples is, in a precise sense, equivalent to the existence of Armstrong bases (a relaxation of the classical notion of Armstrong databases). After this, we show that every schema mapping specified by LAV s-t tgds is uniquely characterized by a finite set of universal examples with respect to the class of LAV s-t tgds. Moreover, this positive result extends to the much broader classes of n-modular schema mappings, n a positive integer. Finally, we study the unique characterizability of GAV schema mappings. It turns out that some GAV schema mappings are uniquely characterizable by a finite set of universal examples with respect to the class of GAV s-t tgds, while others are not. By unveiling a tight connection with homomorphism dualities, we establish an effective, sound, and complete criterion for determining whether or not a GAV schema mapping is uniquely characterizable by a finite set of universal examples with respect to the class of GAV s-t tgds.