Evaluating a Temporal Relational Algebra Supporting Preferences in Temporal Relational Databases

Though a plethora of different approaches have been devoted to the treatment of time within the relational context, temporal preferences have not been faced yet. In several tasks and applications (e.g., planning, scheduling, workflows, guidelines), the exact time of occurrence of facts is not known (i.e., time is indeterminate), and preferences can be assigned to the different temporal possibilities. In a recent paper, we have laid the theoretical basis of the treatment of preferential indeterminate time in temporal relational databases, by proposing a relational representation and a temporal relational algebra to manage it, and studying their theoretical properties (e.g., correctness, reducibility). In this paper, we assess such a theoretical framework in terms of performance evaluation along different dimensions, and study the overhead added to cope with preferences with respect to relational approaches (i) without time, (ii) with exact time, and (iii) with indeterminate time (but no preferences).