Querying object-oriented databases
SIGMOD '92 Proceedings of the 1992 ACM SIGMOD international conference on Management of data
From structured documents to novel query facilities
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Evaluating queries with generalized path expressions
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Rewriting of regular expressions and regular path queries
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data on the Web: from relations to semistructured data and XML
Data on the Web: from relations to semistructured data and XML
Theory of answering queries using views
ACM SIGMOD Record
Querying Semistructured Heterogeneous Information
DOOD '95 Proceedings of the Fourth International Conference on Deductive and Object-Oriented Databases
Representative Objects: Concise Representations of Semistructured, Hierarchial Data
ICDE '97 Proceedings of the Thirteenth International Conference on Data Engineering
Optimizing Regular Path Expressions Using Graph Schemas
ICDE '98 Proceedings of the Fourteenth International Conference on Data Engineering
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Adding Structure to Unstructured Data
ICDT '97 Proceedings of the 6th 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
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Search Optimization in Semistructured Databases Using Hierarchy of Document Schemas
Programming and Computing Software
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Regular path expressions are essential for formulating queries over the semistructured data without specifying the exact structure. The query pruning is an important optimization technique to avoid useless traversals in evaluating regular path expressions. While the previous query pruning optimizes a single regular path expression well, it often fails to fully optimize multiple regular path expressions. Nevertheless, multiple regular path expressions are very frequently used in nontrivial queries, and so an effective optimization technique for them is required. In this paper, we present a new technique called the two-phase query pruning that consists of the preprocessing phase and the pruning phase. Our two-phase query pruning is effective in optimizing multiple regular path expressions, and is more scalable and efficient than the combination of the previous query pruning and post-processing in that it never deals with exponentially many combinations of sub-results produced from all the regular path expressions.