Optimal Incremental Evaluation of Preference Queries Based on Ranked Sub-queries

We consider the problem of sufficiently answer preference queries when access to the database is through a set of ranked lists and preferences define a strict partial order over the database objects. The iMPO-1 algorithm we introduce minimizes the number of database accesses and can also incrementally return objects as soon as they are guaranteed to be part of the result. As such it generalizes known techniques developed for specific cases, such as Skyline querie