Dependencies revisited for improving data quality
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Semantics in Data and Knowledge Bases
XML with incomplete information: models, properties, and query answering
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Inclusion Dependencies in XML: Extending Relational Semantics
DEXA '09 Proceedings of the 20th International Conference on Database and Expert Systems Applications
Keys in XML: Capturing Identification and Uniqueness
WISE '09 Proceedings of the 10th International Conference on Web Information Systems Engineering
XML with incomplete information
Journal of the ACM (JACM)
Consistent query answers from virtually integrated XML data
Journal of Systems and Software
Promoting the semantic capability of XML keys
XSym'10 Proceedings of the 7th international XML database conference on Database and XML technologies
Efficient reasoning about data trees via integer linear programming
Proceedings of the 14th International Conference on Database Theory
Two-variable logic and key constraints on data words
Proceedings of the 14th International Conference on Database Theory
A precious class of cardinality constraints for flexible XML data processing
ER'11 Proceedings of the 30th international conference on Conceptual modeling
When conceptual model meets grammar: A dual approach to XML data modeling
Data & Knowledge Engineering
Design by example for SQL table definitions with functional dependencies
The VLDB Journal — The International Journal on Very Large Data Bases
ACM Transactions on Database Systems (TODS)
Efficient reasoning about data trees via integer linear programming
ACM Transactions on Database Systems (TODS)
An Automata Model for Trees with Ordered Data Values
LICS '12 Proceedings of the 2012 27th Annual IEEE/ACM Symposium on Logic in Computer Science
Containment of pattern-based queries over data trees
Proceedings of the 16th International Conference on Database Theory
Reasoning about functional and full hierarchical dependencies over partial relations
Information Sciences: an International Journal
APCCM '13 Proceedings of the Ninth Asia-Pacific Conference on Conceptual Modelling - Volume 143
Reasoning about pattern-based XML queries
RR'13 Proceedings of the 7th international conference on Web Reasoning and Rule Systems
Efficiency frontiers of XML cardinality constraints
Data & Knowledge Engineering
Extending two-variable logic on data trees with order on data values and its automata
ACM Transactions on Computational Logic (TOCL)
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XML specifications often consist of a type definition (typically, a document type definition (DTD)) and a set of integrity constraints. It has been shown previously that such specifications can be inconsistent, and thus it is often desirable to check consistency at compile time. It is known [W. Fan and L. Libkin, J. ACM, 49 (2002), pp. 368-406] that for general keys, foreign keys, and DTDs the consistency problem is undecidable; however, it becomes NP-complete when all keys are one-attribute (unary) and tractable, if no foreign keys are used. In this paper, we consider a variety of previously studied constraints for XML data and investigate the complexity of the consistency problem. Our main conclusion is that, in the presence of foreign key constraints, compile-time verification of consistency is infeasible. We look at absolute constraints that hold in the entire document and relative constraints that hold only in a part of the document. For absolute constraints, we prove decidability and establish complexity bounds for primary multiattribute keys and unary foreign keys and study unary constraints that involve regular expressions. For relative constraints, we prove that even for unary constraints the consistency problem is undecidable. We also show that results continue to hold for extended DTDs, a more expressive typing mechanism for XML.