Data on the Web: from relations to semistructured data and XML
Data on the Web: from relations to semistructured data and XML
Integrating keyword search into XML query processing
Proceedings of the 9th international World Wide Web conference on Computer networks : the international journal of computer and telecommunications netowrking
Flexible queries over semistructured data
PODS '01 Proceedings of the twentieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
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
EDBT '02 Proceedings of the 8th International Conference on Extending Database Technology: Advances in Database Technology
Querying XML Documents Made Easy: Nearest Concept Queries
Proceedings of the 17th International Conference on Data Engineering
DataGuides: Enabling Query Formulation and Optimization in Semistructured Databases
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
Views in a Large Scale XML Repository
Proceedings of the 27th 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
The VLDB Journal — The International Journal on Very Large Data Bases
XRANK: ranked keyword search over XML documents
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Structural Joins: A Primitive for Efficient XML Query Pattern Matching
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Exploiting Local Similarity for Indexing Paths in Graph-Structured Data
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Efficient keyword search for smallest LCAs in XML databases
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Benefits of path summaries in an XML query optimizer supporting multiple access methods
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
Keyword Proximity Search in XML Trees
IEEE Transactions on Knowledge and Data Engineering
Containment of Partially Specified Tree-Pattern Queries
SSDBM '06 Proceedings of the 18th International Conference on Scientific and Statistical Database Management
Forward node-selecting queries over trees
ACM Transactions on Database Systems (TODS)
XSEarch: a semantic search engine for XML
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
Enabling Schema-Free XQuery with meaningful query focus
The VLDB Journal — The International Journal 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
A heuristic approach for checking containment of generalized tree-pattern queries
Proceedings of the 17th ACM conference on Information and knowledge management
Efficient Evaluation of Generalized Tree-Pattern Queries with Same-Path Constraints
SSDBM 2009 Proceedings of the 21st International Conference on Scientific and Statistical Database Management
Efficient evaluation of generalized tree-pattern queries on XML streams
The VLDB Journal — The International Journal on Very Large Data Bases
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The wide adoption of XML has increased the interest on data models that are based on tree-structured data. Querying capabilities are provided through tree-pattern queries (TPQs). The need for querying tree-structured data sources when their structure is not fully known, and the need to integrate multiple data sources with different tree structures have driven, recently, the suggestion of query languages that relax the complete specification of a tree pattern. Assigning semantics to the queries of these languages so that they return meaningful answers is a challenging issue. In this paper, we introduce a query language which allows the specification of partial tree-pattern queries (PTPQs). The structure in a PTPQ can be flexibly specified fully, partially or not at all. We define index graphs which summarize the structural information of data trees. Using index graphs, we show that PTPQs can be evaluated through the generation of an equivalent set of ''complete'' TPQs. We suggest an original approach that exploits the set of complete TPQs of a PTPQ to assign meaningful semantics to the PTPQ language. In contrast to previous approaches that operate locally on the data to compute meaningful answers (usually by computing lowest common ancestors), our approach operates globally on index graphs to detect meaningful complete TPQs. We implemented and experimentally evaluated our approach on DBLP-based data sets with irregularities. Its comparison to previous ones shows that it succeeds in finding all the meaningful answers when the others fail (perfect recall). Further, it outperforms approaches with similar recall in excluding meaningless answers (better precision). Finally, it is superior to and scales better than the only previous approach that allows for structural constraints in the queries. Our approach generates TPQs and therefore, it can be easily implemented on top of an XQuery engine.