A Proof Procedure for Data Dependencies
Journal of the ACM (JACM)
Logic programming and databases
Logic programming and databases
Algorithms from P to NP (vol. 1): design and efficiency
Algorithms from P to NP (vol. 1): design and efficiency
Discrete Mathematics - Algebraic graph theory; a volume dedicated to Gert Sabidussi
Removing redundancy from a clause
Artificial Intelligence
On the efficiency of subsumption algorithms
Journal of the ACM (JACM)
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The theory of joins in relational databases
ACM Transactions on Database Systems (TODS)
Efficient optimization of a class of relational expressions
ACM Transactions on Database Systems (TODS)
Testing implications of data dependencies
ACM Transactions on Database Systems (TODS)
Horn clauses and database dependencies
Journal of the ACM (JACM)
On the complexity of database queries
Journal of Computer and System Sciences
Conjunctive query containment revisited
Theoretical Computer Science - Special issue on the 6th International Conference on Database Theory—ICDT '97
Conjunctive-query containment and constraint satisfaction
Journal of Computer and System Sciences - Special issue on the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on principles of database systems
A comparison of structural CSP decomposition methods
Artificial Intelligence
The complexity of acyclic conjunctive queries
Journal of the ACM (JACM)
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Query evaluation via tree-decompositions
Journal of the ACM (JACM)
Parameterized complexity for the database theorist
ACM SIGMOD Record
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Data exchange: getting to the core
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Robbers, marshals, and guards: game theoretic and logical characterizations of hypertree width
Journal of Computer and System Sciences - Special issu on PODS 2001
Hypergraphs in Model Checking: Acyclicity and Hypertree-Width versus Clique-Width
SIAM Journal on Computing
Foundations of semantic web databases
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Weighted hypertree decompositions and optimal query plans
PODS '04 Proceedings of the twenty-third 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
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Theory of Relational Databases
Theory of Relational Databases
Data exchange: computing cores in polynomial time
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Hypertree width and related hypergraph invariants
European Journal of Combinatorics
Marshals, monotone marshals, and hypertree-width
Journal of Graph Theory
Proceedings of the 2009 ACM SIGMOD International Conference on Management of data
Concise and expressive mappings with +Spicy
Proceedings of the VLDB Endowment
On chase termination beyond stratification
Proceedings of the VLDB Endowment
Laconic schema mappings: computing the core with SQL queries
Proceedings of the VLDB Endowment
Towards practical feasibility of core computation in data exchange
Theoretical Computer Science
The DL-lite family and relations
Journal of Artificial Intelligence Research
Proceedings of the 13th International Conference on Database Theory
Composition with target constraints
Proceedings of the 13th International Conference on Database Theory
Answering non-monotonic queries in relational data exchange
Proceedings of the 13th International Conference on Database Theory
Static analysis of schema-mappings ensuring oblivious termination
Proceedings of the 13th International Conference on Database Theory
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Querying incomplete data over extended er schemata
Theory and Practice of Logic Programming
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
The complexity of evaluating tuple generating dependencies
Proceedings of the 14th International Conference on Database Theory
ACM Transactions on Database Systems (TODS)
Journal of the ACM (JACM)
Characterisations of multivalued dependency implication over undetermined universes
Journal of Computer and System Sciences
Core schema mappings: Scalable core computations in data exchange
Information Systems
On the data complexity of consistent query answering
Proceedings of the 15th International Conference on Database Theory
Computing universal models under guarded TGDs
Proceedings of the 15th International Conference on Database Theory
What is the IQ of your data transformation system?
Proceedings of the 21st ACM international conference on Information and knowledge management
Towards more expressive ontology languages: The query answering problem
Artificial Intelligence
Solutions and query rewriting in data exchange
Information and Computation
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Data exchange deals with inserting data from one database into another database having a different schema. Fagin et al. [2005] have shown that among the universal solutions of a solvable data exchange problem, there exists—up to isomorphism—a unique most compact one, “the core”, and have convincingly argued that this core should be the database to be materialized. They stated as an important open problem whether the core can be computed in polynomial time in the general setting where the mapping between the source and target schemas is given by source-to-target constraints that are arbitrary tuple generating dependencies (tgds) and target constraints consisting of equality generating dependencies (egds) and a weakly acyclic set of tgds. In this article, we solve this problem by developing new methods for efficiently computing the core of a universal solution. This positive result shows that data exchange based on cores is feasible and applicable in a very general setting. In addition to our main result, we use the method of hypertree decompositions to derive new algorithms and upper bounds for query containment checking and computing cores of arbitrary database instances. We also show that computing the core of a data exchange problem is fixed-parameter intractable with respect to a number of relevant parameters, and that computing cores is NP-complete if the rule bodies of target tgds are augmented by a special predicate that distinguishes a null value from a constant data value.