An evaluation model for clustering strategies in the O2 object-oriented database system
ICDT '90 Proceedings of the third international conference on database theory on Database theory
Clustering strategies in O2: an overview
Building an object-oriented database system
Validating streaming XML documents
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
EDBT '02 Proceedings of the Worshops XMLDM, MDDE, and YRWS on XML-Based Data Management and Multimedia Engineering-Revised Papers
Processing XML streams with deterministic automata and stream indexes
ACM Transactions on Database Systems (TODS)
A gentle introduction to semantic subtyping
PPDP '05 Proceedings of the 7th ACM SIGPLAN international conference on Principles and practice of declarative programming
Accelerating queries by pruning XML documents
Data & Knowledge Engineering
Taxonomy of XML schema languages using formal language theory
ACM Transactions on Internet Technology (TOIT)
MonetDB/XQuery: a fast XQuery processor powered by a relational engine
Proceedings of the 2006 ACM SIGMOD international conference on Management of data
Inference of concise DTDs from XML data
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
A system for the static analysis of XPath
ACM Transactions on Information Systems (TOIS)
On the complexity of nonrecursive XQuery and functional query languages on complex values
ACM Transactions on Database Systems (TODS)
XMark: a benchmark for XML data management
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
Staircase join: teach a relational DBMS to watch its (axis) steps
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
XPath satisfiability in the presence of DTDs
Journal of the ACM (JACM)
Learning deterministic regular expressions for the inference of schemas from XML data
Proceedings of the 17th international conference on World Wide Web
Semantic subtyping: Dealing set-theoretically with function, union, intersection, and negation types
Journal of the ACM (JACM)
ACM Computing Surveys (CSUR)
Patterns and types for querying XML documents
DBPL'05 Proceedings of the 10th international conference on Database Programming Languages
Which XML schemas admit 1-pass preorder typing?
ICDT'05 Proceedings of the 10th international conference on Database Theory
XPathMark: an XPath benchmark for the XMark generated data
XSym'05 Proceedings of the Third international conference on Database and XML Technologies
A full pattern-based paradigm for XML query processing
PADL'05 Proceedings of the 7th international conference on Practical Aspects of Declarative Languages
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XML data projection (or pruning) is a natural optimization for main memory query engines: given a query Q over a document D, the subtrees of D that are not necessary to evaluate Q are pruned, thus producing a smaller document D'; the query Q is then executed on D', hence avoiding to allocate and process nodes that will never be reached by Q. In this article, we propose a new approach, based on types, that greatly improves current solutions. Besides providing comparable or greater precision and far lesser pruning overhead, our solution—unlike current approaches—takes into account backward axes, predicates, and can be applied to multiple queries rather than just to single ones. A side contribution is a new type system for XPath able to handle backward axes. The soundness of our approach is formally proved. Furthermore, we prove that the approach is also complete (i.e., yields the best possible type-driven pruning) for a relevant class of queries and Schemas. We further validate our approach using the XMark and XPathMark benchmarks and show that pruning not only improves the main memory query engine's performances (as expected) but also those of state of the art native XML databases.