Query optimisation for web data sources: minimisation of the number of accesses
Andrea Calı̀, Davide Martinenghi, Domenico Carbotta · BIROn (Birkbeck, University of London) · 2007
When relational data have access constraints that require certain attributes to be selected in queries, as in the case of (wrapped) Web sources accessible via forms, a recursive query plan is needed to answer queries at best. We present a query plan optimisation technique for several classes of queries that minimises the number of accesses according to a novel, strong notion of minimality. We provide experimental evidence of the effectiveness of our technique.