Algebras for querying text regions (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
On supporting containment queries in relational database management systems
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
Covering indexes for branching path queries
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
Holistic twig joins: optimal XML pattern matching
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
Index Structures for Path Expressions
ICDT '99 Proceedings of the 7th International Conference on Database Theory
DataGuides: Enabling Query Formulation and Optimization in Semistructured Databases
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
EDBT '02 Proceedings of the Worshops XMLDM, MDDE, and YRWS on XML-Based Data Management and Multimedia Engineering-Revised Papers
XPath queries on streaming data
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Efficient processing of XML twig queries with OR-predicates
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
Proceedings of the thirteenth ACM international conference on Information and knowledge management
Efficient processing of XML twig patterns with parent child edges: a look-ahead approach
Proceedings of the thirteenth ACM international conference on Information and knowledge management
On the memory requirements of XPath evaluation over XML streams
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On boosting holism in XML twig pattern matching using structural indexing techniques
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Efficient algorithms for processing XPath queries
ACM Transactions on Database Systems (TODS)
Stack-based algorithms for pattern matching on DAGs
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Semantic querying of tree-structured data sources using partially specified tree patterns
Proceedings of the 14th ACM international conference on Information and knowledge management
An Efficient XPath Query Processor for XML Streams
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
MonetDB/XQuery: a fast XQuery processor powered by a relational engine
Proceedings of the 2006 ACM SIGMOD international conference on Management of data
Twig2Stack: bottom-up processing of generalized-tree-pattern queries over XML documents
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
Forward node-selecting queries over trees
ACM Transactions on Database Systems (TODS)
Efficient algorithms for evaluating xpath over streams
Proceedings of the 2007 ACM SIGMOD international conference on Management of data
Efficient structural joins on indexed XML documents
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Holistic twig joins on indexed XML documents
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Evaluation of partial path queries on xml data
Proceedings of the sixteenth ACM conference on Conference on information and knowledge management
Assigning semantics to partial tree-pattern queries
Data & Knowledge Engineering
Structured materialized views for XML queries
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
Querying complex structured databases
VLDB '07 Proceedings of the 33rd international conference on Very large data bases
Efficient evaluation of generalized path pattern queries on XML data
Proceedings of the 17th international conference on World Wide Web
Containment of partially specified tree-pattern queries in the presence of dimension graphs
The VLDB Journal — The International Journal on Very Large Data Bases
Indexing dataspaces with partitions
World Wide Web
Querying and ranking incomplete twigs in probabilistic XML
World Wide Web
A survey on XML streaming evaluation techniques
The VLDB Journal — The International Journal on Very Large Data Bases
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Finding the occurrences of structural patterns in XML data is a key operation in XML query processing. Existing algorithms for this operation focus almost exclusively on path patterns or tree patterns. Current applications of XML require querying of data whose structure is complex or is not fully known to the user, or integrating XML data sources with different structures. These applications have motivated recently the introduction of query languages that allow a partial specification of path patterns in a query. In this paper, we consider partial path queries, a generalization of path pattern queries, and we focus on their efficient evaluation under the indexed streaming evaluation model. Our approach explicitly deals with repeated labels (that is, multiple occurrences of the same label in a query). We show that partial path queries can be represented as rooted dags for which a topological ordering of the nodes exists. We present three algorithms for the efficient evaluation of these queries. The first one exploits a structural summary of data to generate a set of path patterns that together are equivalent to a partial path query. To evaluate these path patterns, we extend a previous algorithm for path-pattern queries so that it can work on path patterns with repeated labels. The second one extracts a spanning tree from the query dag, uses a stack-based algorithm to find the matches of the root-to-leaf paths in the tree, and merge-joins the matches to compute the answer. Finally, the third one exploits multiple pointers of stack entries and a topological ordering of the query dag to apply a stack-based holistic technique. We analyze our algorithms and perform extensive experimental evaluations. Our experimental results show that the holistic algorithm outperforms the other ones. Our approaches are the first ones to efficiently evaluate this class of queries in the indexed streaming model.