On conjunctive queries containing inequalities
Journal of the ACM (JACM)
The hypernode model and its associated query language
JCIT Proceedings of the fifth Jerusalem conference on Information technology
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth 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
Answering queries using views with arithmetic comparisons
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Optimizing Queries with Materialized Views
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
A Scalable Algorithm for Answering Queries Using Views
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Querying Heterogeneous Information Sources Using Source Descriptions
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Answering queries using views: A survey
The VLDB Journal — The International Journal on Very Large Data Bases
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Query planning and optimization in information integration
Query planning and optimization in information integration
Query-answering algorithms for information agents
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
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The problem of answering queries using views is concerned with finding answers to a query using only answers to views. In data integration context with the Local-As-Views approach, this problem translates to finding maximally contained rewriting for a given query. Existing solutions follow a bottom-up approach and, for efficiency reason, often require a post-processing phase, which comes at an additional cost.We propose a solution which follows a top-down approach. For this, we first present a graph-based model for conjunctive queries and views, and identify conditions that if satisfied ensures maximality of a rewriting. Using this model as a basis, we then introduce a novel top-down algorithm, TreeWise, which efficiently generates maximally contained rewritings which are in general less expensive to evaluate, compared to the bottom-up algorithms, without requiring post-processing. The preliminary results of our experiments indicate that while TreeWise has comparable performance, it generally produces better quality rewritings.