Journal of Computer and System Sciences - 3rd Annual Conference on Structure in Complexity Theory, June 14–17, 1988
A catalog of complexity classes
Handbook of theoretical computer science (vol. A)
Normal forms and conservative extension properties for query languages over collection types
Journal of Computer and System Sciences
Bounded fixpoints for complex objects
Theoretical Computer Science
Possibilities and limitations of using flat operators in nested algebra expressions
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Equivalence and normal forms for the restricted and bounded fixpoint in the nested algebra
Information and Computation
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
SilkRoute: A framework for publishing relational data in XML
ACM Transactions on Database Systems (TODS)
Quilt: An XML Query Language for Heterogeneous Data Sources
Selected papers from the Third International Workshop WebDB 2000 on The World Wide Web and Databases
Eliminating definitions and Skolem functions in first-order logic
ACM Transactions on Computational Logic (TOCL)
First-order logic with two variables and unary temporal logic
Information and Computation - Special issue: LICS'97
A comprehensive XQuery to SQL translation using dynamic interval encoding
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Recursive XML Schemas, Recursive XML Queries, and Relational Storage: XML-to-SQL Query Translation
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
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)
Conjunctive queries over trees
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Arithmetic, first-order logic, and counting quantifiers
ACM Transactions on Computational Logic (TOCL)
Efficient algorithms for processing XPath queries
ACM Transactions on Database Systems (TODS)
Query translation from XPATH to SQL in the presence of recursive DTDs
VLDB '05 Proceedings of the 31st international conference on Very large data bases
On the complexity of nonrecursive XQuery and functional query languages on complex values
ACM Transactions on Database Systems (TODS)
Efficient XML-to-SQL query translation: where to add the intelligence?
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
ACM Computing Surveys (CSUR)
Interpreting tree-to-tree queries
ICALP'06 Proceedings of the 33rd international conference on Automata, Languages and Programming - Volume Part II
On the expressive power of XQuery fragments
DBPL'05 Proceedings of the 10th international conference on Database Programming Languages
First order paths in ordered trees
ICDT'05 Proceedings of the 10th international conference on Database Theory
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Destabilizers and independence of XML updates
Proceedings of the VLDB Endowment
Foundations of XML based on logic and automata: a snapshot
FoIKS'12 Proceedings of the 7th international conference on Foundations of Information and Knowledge Systems
Highly expressive query languages for unordered data trees
Proceedings of the 15th International Conference on Database Theory
Optimising XML---RDF data integration: a formal approach to improve XSPARQL efficiency
ESWC'12 Proceedings of the 9th international conference on The Semantic Web: research and applications
XML query-update independence analysis revisited
Proceedings of the 2012 ACM symposium on Document engineering
A declarative embedding of XQuery in a functional-logic language
LOPSTR'11 Proceedings of the 21st international conference on Logic-Based Program Synthesis and Transformation
Hi-index | 0.00 |
Predicate logic has long been seen as a good foundation for querying relational data. This is embodied in the correspondence between relational calculus and first-order logic, and can also be seen in mappings from fragments of the standard relational query language SQL to extensions of first-order logic (e.g. with counting). A key question is what is the analog to this correspondence for querying tree-structured data, as seen, for example, in XML documents. We formalize this as the question of the appropriate logical query language for defining transformations on tree-structured data. The predominant practitioner paradigm for defining such transformations is top-down tree building. This is embodied by the XQuery query language, which builds the output tree in parallel starting at the root, based on variable bindings and nodeset queries in the XPath language. The goal of this article is to compare the expressiveness of top-down tree-building languages based on a benchmark of predicate logic. We start by giving a formalized XQuery XQ that can serve as a representative of the top-down approach. We show that all queries in XQ with only atomic equality are equivalent to first-order interpretations, an analog to first-order logic (FO) in the setting of transformations of tree-structured data. We then consider fragments of atomic XQ. We identify a fragment that maps efficiently into first-order, a fragment that maps into existential first-order logic, and a fragment that maps into the navigationally two-variable fragment of first-order logic—an analog of two-variable logic in the setting where data values are unbounded. When XQ is considered with deep equality, we find that queries can be translated into FO with counting (FO(Cnt)). Translations from XQ to logical languages on relations have a number of consequences. We use them to derive complexity bounds for XQ fragments, and to bound the Boolean expressiveness of XQ fragments.