Subtree-elimination algorithms in deductive databases
Subtree-elimination algorithms in deductive databases
Contexts: a formalization and some applications
Contexts: a formalization and some applications
Data model and query evaluation in global information systems
Journal of Intelligent Information Systems - Special issue: networked information discovery and retrieval
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
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 caching and optimization in distributed mediator systems
SIGMOD '96 Proceedings of the 1996 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
InfoSleuth: agent-based semantic integration of information in open and dynamic environments
SIGMOD '97 Proceedings of the 1997 ACM SIGMOD international conference on Management of data
Answering recursive queries using views
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Deciding equivalences among aggregate queries
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
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Modeling Web sources for information integration
AAAI '98/IAAI '98 Proceedings of the fifteenth national/tenth conference on Artificial intelligence/Innovative applications of artificial intelligence
Flexible and scalable cost-based query planning in mediators: a transformational approach
Artificial Intelligence - Special issue on Intelligent internet systems
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Information Integration Using Logical Views
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Conjunctive Query Containment Revisited
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Don't Scrap It, Wrap It! A Wrapper Architecture for Legacy Data Sources
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
Optimizing Queries Across Diverse Data Sources
VLDB '97 Proceedings of the 23rd 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 Regular Path Queries Using Views
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Query planning and optimization in information integration
Query planning and optimization in information integration
Planning to gather inforrnation
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
Query-answering algorithms for information agents
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
The limits on combining recursive horn rules with description logics
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
Quantificational logic of context
AAAI'96 Proceedings of the thirteenth national conference on Artificial intelligence - Volume 1
A task-oriented agent-based mechanism for mathematical assistant systems
Web Intelligence and Agent Systems
Proceedings of the 28th international conference on Software engineering
ACM Computing Surveys (CSUR)
Deploying information agents on the web
IJCAI'03 Proceedings of the 18th international joint conference on Artificial intelligence
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Integrating data from heterogeneous data sources is a critical problem that has received a great deal of attention in recent years. There are two competing approaches to address this problem. The traditional approach, which first appeared in Multibase and more recently in HERMES and TSIMMIS, often called global-as-view, defines the global model as a view on the sources. A more recent approach, sometimes referred to as local-as-view or view rewriting, defines the sources as views on the global model. The disadvantage of the first approach is that a person must re-engineer the definitions of the global model whenever any of the sources change or when new sources are added. The view rewriting approach does not suffer from this drawback, but the problem of rewriting queries into equivalent plans using views is computationally hard and must be performed for each query at run-time.In this paper we propose a hybrid approach that amortizes the cost of query processing over all queries by pre-compiling the source descriptions into a minimal set of integration axioms. Using this approach, the sources are defined in terms of the global model and then compiled into axioms that define the global model in terms of the sources. These axioms can be efficiently instantiated at run-time to determine the most appropriate rewriting to answer a query and facilitate traditional cost-based query optimization. Our approach combines the flexibility of the local-as-view approach with the run-time efficiency of the query processing in global-as-view systems. We have implemented this approach for the SIMS and Ariadne information mediators and provide empirical results that demonstrate that in practice the approach scales to large numbers of sources and that the approach can compile the axioms for a variety of real-world domains in a matter of seconds.