Foundations of logic programming; (2nd extended ed.)
Foundations of logic programming; (2nd extended ed.)
Intensional query answering by partial evaluation
Journal of Intelligent Information Systems
Managing semantic heterogeneity in databases: a theoretical prospective
PODS '97 Proceedings of the sixteenth 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
Capability based mediation in TSIMMIS
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Logical approaches to incomplete information: a survey
Logics for databases and information systems
The entity-relationship model—toward a unified view of data
ACM Transactions on Database Systems (TODS) - Special issue: papers from the international conference on very large data bases: September 22–24, 1975, Framingham, MA
Intensional and extensional integration and abstraction of heterogeneous databases
Data & Knowledge Engineering
Theory of answering queries using views
ACM SIGMOD Record
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Logic-based techniques in data integration
Logic-based artificial intelligence
Query Folding with Inclusion Dependencies
ICDE '98 Proceedings of the Fourteenth International Conference on Data Engineering
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
Information Integration Using Logical Views
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Tableau Techniques for Querying Information Sources through Global Schemas
ICDT '99 Proceedings of the 7th International Conference on Database Theory
Model-Based Mediation with Domain Maps
Proceedings of the 17th International Conference on Data Engineering
Information Integration: Conceptual Modeling and Reasoning Support
COOPIS '98 Proceedings of the 3rd IFCIS International Conference on Cooperative Information Systems
View-Based Query Processing and Constraint Satisfaction
LICS '00 Proceedings of the 15th Annual IEEE Symposium on Logic in Computer Science
Towards heterogeneous multimedia information systems: the Garlic approach
RIDE '95 Proceedings of the 5th International Workshop on Research Issues in Data Engineering-Distributed Object Management (RIDE-DOM'95)
Answering Regular Path Queries Using Views
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Query Planning with Limited Source Capabilities
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Data Integration Is Harder than You Thought
CooplS '01 Proceedings of the 9th International Conference on Cooperative Information Systems
Conceptual Integration of Multiple Partial Geometric Models
ER '02 Proceedings of the 21st International Conference on Conceptual Modeling
On the decidability and complexity of query answering over inconsistent and incomplete databases
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Source integration for data warehousing
Multidimensional databases
Data integration: a logic-based perspective
AI Magazine - Special issue on semantic integration
Tractable Query Answering over Conceptual Schemata
ER '09 Proceedings of the 28th International Conference on Conceptual Modeling
IBIS: semantic data integration at work
CAiSE'03 Proceedings of the 15th international conference on Advanced information systems engineering
Querying incomplete data over extended er schemata
Theory and Practice of Logic Programming
Query answering under expressive entity-relationship schemata
ER'10 Proceedings of the 29th international conference on Conceptual modeling
Querying conceptual schemata with expressive equality constraints
ER'11 Proceedings of the 30th international conference on Conceptual modeling
Containment of conjunctive queries over conceptual schemata
DASFAA'06 Proceedings of the 11th international conference on Database Systems for Advanced Applications
Ontological query answering under expressive Entity-Relationship schemata
Information Systems
First-Order patterns for information integration
ICWE'05 Proceedings of the 5th international conference on Web Engineering
A general Datalog-based framework for tractable query answering over ontologies
Web Semantics: Science, Services and Agents on the World Wide Web
Taming the infinite chase: query answering under expressive relational constraints
Journal of Artificial Intelligence Research
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Data integration systems provide access to a set of heterogeneous, autonomous data sources through a so-called global, or mediated view. There is a general consensus that the best way to describe the global view is through a conceptual data model, and that there are basically two approaches for designing a data integration system. In the global-as-view approach, one defines the concepts in the global schema as views over the sources, whereas in the local-as-view approach, one characterizes the sources as views over the global schema. It is well known that processing queries in the latter approach is similar to query answering with incomplete information, and, therefore, is a complex task. On the other hand, it is a common opinion that query processing is much easier in the former approach. In this paper we show the surprising result that, when the global schema is expressed in terms of a conceptual data model, even a very simple one, query processing becomes difficult in the global-as-view approach also. We demonstrate that the problem of incomplete information arises in this case too, and we illustrate some basic techniques for effectively answering queries posed to the global schema of the data integration system.