Discrete Mathematics - Algebraic graph theory; a volume dedicated to Gert Sabidussi
Logical approaches to incomplete information: a survey
Logics for databases and information systems
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Locally consistent transformations and query answering in data exchange
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
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
Data exchange: on the complexity of answering queries with inequalities
Information Processing Letters
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
The complexity of data exchange
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
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
Data exchange and incomplete information
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Update exchange with mappings and provenance
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
Answering aggregate queries in data exchange
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data exchange and schema mappings in open and closed worlds
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Logical foundations of relational data exchange
ACM SIGMOD Record
Normalization and optimization of schema mappings
Proceedings of the VLDB Endowment
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
On the tradeoff between mapping and querying power in XML 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
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
Data exchange and schema mappings in open and closed worlds
Journal of Computer and System Sciences
Proceedings of the 4th International Workshop on Logic in Databases
ACM Transactions on Database Systems (TODS)
Normalization and optimization of schema mappings
The VLDB Journal — The International Journal on Very Large Data Bases
On the data complexity of consistent query answering
Proceedings of the 15th International Conference on Database Theory
Representation systems for data exchange
Proceedings of the 15th International Conference on Database Theory
Collaborative data sharing via update exchange and provenance
ACM Transactions on Database Systems (TODS)
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Data exchange deals with the following problem: given an instance over a source schema, a specification of the relationship between the source and the target,and dependencies on the target, construct an instance over a target schema that satisfies the given relationships and dependencies. Recently - for data exchange settings without target dependencies - Libkin (PODS'06) introduced a new concept of solutions based on the closed world assumption (so calledCWA-solutions), and showed that, in some respects, this new notion behaves better than the standard notion of solutions considered in previous papers on data exchange. The present paper extends Libkin's notion of CWA-solutions to data exchange settings with target dependencies. We show that, when restricting attention to data exchange settings with weakly acyclic target dependencies, this new notion behaves similarly as before: the core is the unique "minimal" CWA-solution, and computing CWA-solutions as well as certain answers to positive queries is possible in polynomial time and can be PTIME-hard. However, there may be more than one "maximal" CWA-solution. And going beyond the class of positive queries, we obtain that there are conjunctive queries with (just) one inequality, for which evaluating the certain answers is coNP-hard. Finally, we consider the EXISTENCE-OF-CWA-SOLUTIONS problem: while the problem is tractable for data exchange settings with weakly acyclic target dependencies, it turns out to be undecidable for general data exchange settings. As a consequence, we obtain that also the EXISTENCE-OF-UNIVERSAL-SOLUTIONS problem is undecidable in genera.