Abstract

Time is unbounded by nature. A temporal predicate (one that varies with time) will thus often have an infinite extension. To store such a predicate in a database, one can either artificially restrict its extension to a finite set or, more desirably, use a formalism that allows the finite representation of at least some infinite temporal extensions. Several such formalisms have been proposed in the past few years. The formalism that extends traditional relational databases most directly is the generalized databases described in [KSW90]. There, database tuples are extended with an arbitrary number of additional columns carrying linear repeating points. These represent periodic sets of time points possibly constrained by linear inequalities. The query language proposed in [KSW90] is a multi-sorted first-order logic in which predicates have...

Citations