Temporal Databases: Beyond Finite Extensions (position paper)

We argue that temporal databases should not be restricted to relations with finite extensions. many temporal events are periodic and have no natural bounds. Moreover, such events have a more compact representation when allowed to be unbounded. We present two formalisms for representing and querying possibly infinite periodic data and discuss some of their properties, including expressiveness and query evaluation complexity. Finally, we turn to implementation issues and argue that significant extensions to existing database systems are necessary in order to implement the frameworks we describe.