A Relational Algebra for Streaming Tables Living in a Temporal Database World

The recently introduced streaming table concept, a fully native representation of streaming data inside a DBMS, enabled modern data-intensive applications with one-time queries (OTQs) and continuous queries (CQs) capabilities on both streaming and standard relational tables. In this paper, we fully acknowledge the temporal nature of streaming tables and we propose to go one step further and integrate them in a temporal DBMS context, where time management is native. Our aim is to break the traditional barrier between the streaming and the temporal worlds, offering complete interoperability between streams and temporal data. To this end, we present a continuous temporal algebra supporting both OTQs and CQs seamlessly on streaming, standard and temporal relational tables. We further show how the transition from continuous to one-time semantics can be managed by defining suitable translation rules, which can also be used as a basis for the implementation of the proposed continuous algebra in a temporal DBMS.