Foundations of logic programming; (2nd extended ed.)
Foundations of logic programming; (2nd extended ed.)
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
The relational model for database management: version 2
The relational model for database management: version 2
Logic-based approach to semantic query optimization
ACM Transactions on Database Systems (TODS)
Reformulating query plans for multidatabase systems
CIKM '93 Proceedings of the second international conference on Information and knowledge management
Empirical methods for artificial intelligence
Empirical methods for artificial intelligence
Data model and query evaluation in global information systems
Journal of Intelligent Information Systems - Special issue: networked information discovery and retrieval
Information translation, mediation, and mosaic-based browsing in the TSIMMIS system
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
Query reformulation for dynamic information integration
Journal of Intelligent Information Systems - Special issue on intelligent integration of information
Using inductive learning to generate rules for semantic query optimization
Advances in knowledge discovery and data mining
Query Optimization in Database Systems
ACM Computing Surveys (CSUR)
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Design and Implementation of a Semantic Query Optimizer
IEEE Transactions on Knowledge and Data Engineering
Automatic Knowledge Acquisition and Maintenance for Semantic Query Optimization
IEEE Transactions on Knowledge and Data Engineering
Semantic Query Optimization for Tree and Chain Queries
IEEE Transactions on Knowledge and Data Engineering
Learning Transformation Rules for Semantic Query Optimization: A Data-Driven Approach
IEEE Transactions on Knowledge and Data Engineering
Performing Group-By before Join
Proceedings of the Tenth International Conference on Data Engineering
A Formal Model of Trade-off between Optimization and Execution Costs in Semantic Query Optimization
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
Query Optimization by Predicate Move-Around
VLDB '94 Proceedings of the 20th 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
Mariposa: a wide-area distributed database system
The VLDB Journal — The International Journal on Very Large Data Bases
Query optimization by semantic reasoning
Query optimization by semantic reasoning
Learning effective and robust knowledge for semantic query optimization
Learning effective and robust knowledge for semantic query optimization
Planning executing sensing and replanning for information gathering
IJCAI'95 Proceedings of the 14th international joint conference on Artificial intelligence - Volume 2
Planning to gather inforrnation
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
Semantic search on Internet tabular information extraction for answering queries
Proceedings of the ninth international conference on Information and knowledge management
Extending the Re-use of Query Results at Remote Client Sites
DEXA '00 Proceedings of the 11th International Conference on Database and Expert Systems Applications
Extending and inferring functional dependencies in schema transformation
Proceedings of the thirteenth ACM international conference on Information and knowledge management
Using Constraints to Describe Source Contents in Data Integration Systems
IEEE Intelligent Systems
An ontology based approach to the integration of entity-relationship schemas
Data & Knowledge Engineering - Special issue: ER 2004
Distributed and Parallel Databases
Using ontologies for semantic query optimization of XML database
KDXD'06 Proceedings of the First international conference on Knowledge Discovery from XML Documents
Comparable dependencies over heterogeneous data
The VLDB Journal — The International Journal on Very Large Data Bases
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New applications of information systems, such as electronic commerce and healthcare information systems, need to integrate a large number of heterogeneous databases over computer networks. Answering a query in these applications usually involves selecting relevant information sources and generating a query plan to combine the data automatically. As significant progress has been made in source selection and plan generation, the critical issue has been shifting to query optimization. This paper presents a semantic query optimization (SQO) approach to optimizing query plans of heterogeneous multidatabase systems. This approach provides global optimization for query plans as well as local optimization for subqueries that retrieve data from individual database sources. An important feature of our local optimization algorithm is that we prove necessary and sufficient conditions to eliminate an unnecessary join in a conjunctive query of arbitrary join topology. This feature allows our optimizer to utilize more expressive relational rules to provide a wider range of possible optimizations than previous work in SQO. The local optimization algorithm also features a new data structure called AND-OR implication graphs to facilitate the search for optimal queries. These features allow the global optimization to effectively use semantic knowledge to reduce data transmission cost. We have implemented this approach into the pesto query plan optimizer as a part of the sims information mediator. Experimental results demonstrate that pesto can provide significant savings in query execution cost over query plan execution without optimization.