Ali Kiani

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Heterogeneity of schema and data in information integration complicates metadata management and query processing. We consider a mediator-based approach (MI) to information integration and propose a model theoretic approach to describe integration. In this model, we view the schema of the integration as a 3D space, and assume it is a complete lattice. The(More)
Rewriting of conjunctive queries using views has many applications in database and data integration. We investigate ways to improve performance of rewriting and propose a new algorithm which has two phases. In the first phase, similar to Minicon, we find mapping information , which we call coverages, from subgoals in the query to subgoals in view, and(More)
Answering queries using views has been the subject of numerous studies in database and information integration systems. In this work, we consider conjunctive queries with linear equality constraints. Such queries arise naturally in database applications, (heterogeneous) information integration, and in cooperative information systems. We propose a model for(More)
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