Valid-Time Indeterminacy in Temporal Relational Databases: A Family of Data Models

Valid-time indeterminacy concerns not knowing exactly when a fact holds in the modeled reality. In this paper, we first propose a reference approach (data model and algebra) in which all possible temporal scenarios induced by valid-time indeterminacy can be extensionally modeled. We then specify a family of sixteen more compact representational data models. We demonstrate their correctness with respect to the reference approach and analyze several properties, including their data expressiveness and correctness with respect to the reference approach. Finally, we compare these compact models along several relevant dimensions.