“…On the one hand, the constraint-wish (or mandatory-desired) approach will be presented, used amongst others by Dubois and Prade [16,17] and Bosc et al [10,26,27,29,39], and on the other hand, the satisfied-dissatisfied (or positivenegative) approach will be discussed, used amongst others by Zadrożny et al [47] and De Tré et al [13,30,33]. For both approaches, an overview is given, which consecutively handles the semantics of the actual framework, the evaluation of query conditions within this framework, the ranking of query results and the aggregation of compound query conditions.…”