The Clio project: managing heterogeneity
ACM SIGMOD Record
Tree pattern query minimization
The VLDB Journal — The International Journal on Very Large Data Bases
Schema mappings, data exchange, and metadata management
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
Taxonomy of XML schema languages using formal language theory
ACM Transactions on Internet Technology (TOIT)
Composing schema mappings: Second-order dependencies to the rescue
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Conjunctive queries over trees
Journal of the ACM (JACM)
Model management 2.0: manipulating richer mappings
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
XML data exchange: Consistency and query answering
Journal of the ACM (JACM)
XPath satisfiability in the presence of DTDs
Journal of the ACM (JACM)
Piecewise Testable Tree Languages
LICS '08 Proceedings of the 2008 23rd Annual IEEE Symposium on Logic in Computer Science
Optimizing Conjunctive Queries over Trees Using Schema Information
MFCS '08 Proceedings of the 33rd international symposium on Mathematical Foundations of Computer Science
Complexity of Data Tree Patterns over XML Documents
MFCS '08 Proceedings of the 33rd international symposium on Mathematical Foundations of Computer Science
Logical foundations of relational data exchange
ACM SIGMOD Record
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Conjunctive query containment over trees
DBPL'07 Proceedings of the 11th international conference on Database programming languages
A generic framework for data acquisition and transmission
Advances in Engineering Software
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The task of XML data exchange is to restructure a document conforming to a source schema under a target schema according to certain mapping rules. The rules are typically expressed as source-to-target dependencies using various kinds of patterns, involving horizontal and vertical navigation, as well as data comparisons. The target schema imposes complex conditions on the structure of solutions, possibly inconsistent with the mapping rules. In consequence, for some source documents there may be no solutions. We investigate three problems: deciding if all documents of the source schema can be mapped to a document of the target schema (absolute consistency), deciding if a given document of the source schema can be mapped (solution existence), and constructing a solution for a given source document (solution building). We show that the complexity of absolute consistency is rather high in general, but within the polynomial hierarchy for bounded depth schemas. The combined complexity of solution existence and solution building behaves similarly, but the data complexity turns out to be very low. In addition to this we show that even for much more expressive mapping rules, based on MSO definable queries, absolute consistency is decidable and data complexity of solution existence is polynomial.