Towards a Scalable Query Rewriting Algorithm in Presence of Value Constraints

International audienceIn this paper, we investigate the problem of query rewriting using views in a hybrid language allowing nominals (i.e., individual names) to occur in intentional descriptions. Of particular interest, restricted form of nominals where individual names refer to simple values enable the specification of value constraints, i.e, sets of allowed values for attributes. Such constraints are very useful in practice enabling, for example, fine-grained descriptionof queries and views in integration systems and thus can be exploited to reduce the query processing cost. We use description logics to formalize the problem of query rewriting using views in presence of value constraints and show that the technique of query rewriting can be used to process queries under the certain answer semantics. We propose a sound and complete query rewriting Bucket-like algorithm. Data mining techniques have been used to favor scalability w.r.t. the number of views. Experiments on synthetic datasets have been conducte