SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
A query language and optimization techniques for unstructured data
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Regular path queries with constraints
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Query containment for conjunctive queries with regular expressions
PODS '98 Proceedings of the seventeenth 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
Query rewriting for semistructured data
SIGMOD '99 Proceedings of the 1999 ACM SIGMOD international conference on Management of data
WWW '99 Proceedings of the eighth international conference on World Wide Web
XTRACT: a system for extracting document type descriptors from XML documents
SIGMOD '00 Proceedings of the 2000 ACM SIGMOD international conference on Management of data
MSL — a model for W3C XML schema
Proceedings of the 10th international conference on World Wide Web
Database System Concepts
Access path selection in a relational database management system
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
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
Optimizing Queries with Materialized Views
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
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
Incremental Maintenance for Materialized Views over Semistructured Data
VLDB '98 Proceedings of the 24rd International Conference on Very Large Data Bases
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Relational Databases for Querying XML Documents: Limitations and Opportunities
VLDB '99 Proceedings of the 25th International Conference on Very Large Data Bases
Multiview: A Methodology for Supporting Multiple Views in Object-Oriented Databases
VLDB '92 Proceedings of the 18th International Conference on Very Large Data Bases
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
An Optimization Technique for Answering Regular Path Queries
Selected papers from the Third International Workshop WebDB 2000 on The World Wide Web and Databases
Word problems requiring exponential time(Preliminary Report)
STOC '73 Proceedings of the fifth annual ACM symposium on Theory of computing
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As XML (eXtensible Markup Language) has emerged as a standard for information exchange on the World Wide Web, it has gained attention in database communities to extract information from XML seen as a database model. XML queries are based on regular path queries, which find objects reachable by given regular expressions. To answer many kinds of user queries, it is necessary to evaluate queries that have multiple regular path expressions. However, previous work on subjects such as query rewriting and query optimization in the frame work of semistructured data has usually dealt with a single regular path expression. For queries that have multiple regular path expressions we suggest a two phase optimizing technique: query rewriting using views by finding the mappings from the view's body to the query's body and for rewritten queries, evaluating each query conjunct and combining them. We show that our rewriting algorithm is sound and our query evaluation technique is more efficient than that of previous work on optimizing semistructured queries.