Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Journal of Computer and System Sciences
On the representation and querying of sets of possible worlds
Selected papers of the workshop on Deductive database theory
Complexity of answering queries using materialized views
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Normal form algorithms for extended context-free grammars
Theoretical Computer Science
Data integration: a theoretical perspective
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Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
On XML integrity constraints in the presence of DTDs
Journal of the ACM (JACM)
Containment for XPath Fragments under DTD Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
On the decidability and complexity of query answering over inconsistent and incomplete databases
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Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Conjunctive queries over trees
Journal of the ACM (JACM)
Representing and querying XML with incomplete information
ACM Transactions on Database Systems (TODS)
Expressiveness and complexity of XML Schema
ACM Transactions on Database Systems (TODS)
On the complexity of managing probabilistic XML data
Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
XML data exchange: Consistency and query answering
Journal of the ACM (JACM)
XPath satisfiability in the presence of DTDs
Journal of the ACM (JACM)
Incorporating constraints in probabilistic XML
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Local Hoare reasoning about DOM
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
World-set decompositions: Expressiveness and efficient algorithms
Theoretical Computer Science
On the Complexity of Verifying Consistency of XML Specifications
SIAM Journal on Computing
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
Satisfiability of downward XPath with data equality tests
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
XML with incomplete information: models, properties, and query answering
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The complexity of query containment in expressive fragments of XPath 2.0
Journal of the ACM (JACM)
Conjunctive query containment over trees
DBPL'07 Proceedings of the 11th international conference on Database programming languages
Automata and logics for words and trees over an infinite alphabet
CSL'06 Proceedings of the 20th international conference on Computer Science Logic
Incomplete information and certain answers in general data models
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On the complexity of query answering over incomplete XML documents
Proceedings of the 15th International Conference on Database Theory
Efficient reasoning in proper knowledge bases with unknown individuals
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
Containment of pattern-based queries over data trees
Proceedings of the 16th International Conference on Database Theory
When is naive evaluation possible?
Proceedings of the 32nd symposium on Principles of database systems
Reasoning about pattern-based XML queries
RR'13 Proceedings of the 7th international conference on Web Reasoning and Rule Systems
RR'13 Proceedings of the 7th international conference on Web Reasoning and Rule Systems
Querying Regular Graph Patterns
Journal of the ACM (JACM)
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We study models of incomplete information for XML, their computational properties, and query answering. While our approach is motivated by the study of relational incompleteness, incomplete information in XML documents may appear not only as null values but also as missing structural information. Our goal is to provide a classification of incomplete descriptions of XML documents, and separate features—or groups of features—that lead to hard computational problems from those that admit efficient algorithms. Our classification of incomplete information is based on the combination of null values with partial structural descriptions of documents. The key computational problems we consider are consistency of partial descriptions, representability of complete documents by incomplete ones, and query answering. We show how factors such as schema information, the presence of node ids, and missing structural information affect the complexity of these main computational problems, and find robust classes of incomplete XML descriptions that permit tractable query evaluation.