Finding Regular Simple Paths in Graph Databases
SIAM Journal on Computing
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Answering recursive queries using views
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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
Complexity of answering queries using materialized views
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
Data on the Web: from relations to semistructured data and XML
Data on the Web: from relations to semistructured data and XML
View-based query processing for regular path queries with inverse
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Theory of answering queries using views
ACM SIGMOD Record
Introduction to the Theory of Computation
Introduction to the Theory of Computation
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
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
Information Integration Using Logical Views
ICDT '97 Proceedings of the 6th International Conference on Database Theory
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
An Optimization Technique for Answering Regular Path Queries
Selected papers from the Third International Workshop WebDB 2000 on The World Wide Web and Databases
Answering Regular Path Queries Using Views
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
DB2 goes hybrid: integratng native XML and XQuery with relational data and SQL
IBM Systems Journal
The view selection problem for regular path queries
LATIN'08 Proceedings of the 8th Latin American conference on Theoretical informatics
Certain answers and rewritings for local regular path queries on graph-structured data
Proceedings of the Fourteenth International Database Engineering & Applications Symposium
View-based query answering in Description Logics: Semantics and complexity
Journal of Computer and System Sciences
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Rewriting queries using views is a powerful technique that has applications in query optimization, data integration, data warehousing, etc. Query rewriting in relational databases is by now rather well investigated. However, in the framework of semistructured data the problem of rewriting has received much less attention. In this paper we focus on extracting as much information as possible from algebraic rewritings for the purpose of optimizing regular path queries. The cases when we can find a complete exact rewriting of a query using a set a views are very "ideal". However, there is always information available in the views, even if this information is only partial. We introduce "lower" and "possibility" partial rewritings and provide algorithms for computing them. These rewritings are algebraic in their nature, i.e. we use only the algebraic view definitions for computing the rewritings. We do not use any pairs (tuples) of objects for computing the rewritings. This fact makes them a main memory product, which can be used for reducing secondary memory and remote access. After the main memory algebraic computation of the rewritings there is a second phase, with secondary memory access, for deriving the pairs of objects in the query answer. We give two algorithms for utilizing the partial lower and partial possibility rewritings to decrease the number of secondary memory accesses.