Horn clauses and database dependencies
Journal of the ACM (JACM)
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
Generic Model Management: Concepts And Algorithms (Lecture Notes in Computer Science)
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
Supporting executable mappings in model management
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
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
Data exchange and incomplete information
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Model management 2.0: manipulating richer mappings
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
On reconciling data exchange, data integration, and peer data management
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
ACM Transactions on Database Systems (TODS)
Logical foundations of relational data exchange
ACM SIGMOD Record
Reverse data exchange: coping with nulls
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Bidirectional Transformations: A Cross-Discipline Perspective
ICMT '09 Proceedings of the 2nd International Conference on Theory and Practice of Model Transformations
The recovery of a schema mapping: Bringing exchanged data back
ACM Transactions on Database Systems (TODS)
Inverting schema mappings: bridging the gap between theory and practice
Proceedings of the VLDB Endowment
Composition with target constraints
Proceedings of the 13th International Conference on Database Theory
Proceedings of the 13th International Conference on Database Theory
Composing local-as-view mappings: closure and applications
Proceedings of the 13th International Conference on Database Theory
Composition and inversion of schema mappings
ACM SIGMOD Record
Automatic schema merging using mapping constraints among incomplete sources
CIKM '10 Proceedings of the 19th ACM international conference on Information and knowledge management
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
Updatable and evolvable transforms for virtual databases
Proceedings of the VLDB Endowment
ACM SIGMOD Record
ICMT'12 Proceedings of the 5th international conference on Theory and Practice of Model Transformations
Ontology evolution without tears
Web Semantics: Science, Services and Agents on the World Wide Web
Hi-index | 0.00 |
A schema mapping is a specification that describes how data from a source schema is to be mapped to a target schema. Once the data has been transferred from the source to the target, a natural question is whether one can undo the process and recover the initial data, or at least part of it. In fact, it would be desirable to find a reverse schema mapping from target to source that specifies how to bring the exchanged data back. In this paper, we introduce the notion of a recovery of a schema mapping: it is a reverse mapping M' for a mapping M that recovers sound data with respect to M. We further introduce an order relation on recoveries. This allows us to choose mappings that recover the maximum amount of sound information. We call such mappings maximum recoveries. We study maximum recoveries in detail, providing a necessary and sufficient condition for their existence. In particular, we prove that maximum recoveries exist for the class of mappings specified by FO-to-CQ source-to-target dependencies. This class subsumes the class of source-to-target tuple-generating dependencies used in previous work on data exchange. For the class of mappings specified by FO-to-CQ dependencies, we provide an exponential-time algorithm for computing maximum recoveries, and a simplified version for full dependencies that works in quadratic time. We also characterize the language needed to express maximum recoveries, and we include a detailed comparison with the notion of inverse (and quasi-inverse) mapping previously proposed in the data exchange literature. In particular, we show that maximum recoveries strictly generalize inverses. We study the complexity of some decision problems related to the notions of recovery and maximum recovery. Finally, we report our initial results about a relaxed notion of maximal recovery, showing that it strictly generalizes the notion of maximum recovery.