Unleashing the power of querying streaming data in a temporal database world: A relational algebra approach

Modern data-intensive applications have to manage huge quantities of streaming/relational data and need advanced query capabilities involving combinations of continuous queries (CQs) and one-time queries (OTQs) also requiring the verification of complex temporal conditions. In this paper, we go beyond the disjointed panorama of current approaches and adopt a new holistic approach to the integration of stream processing capabilities into the temporal database world based on the streaming table concept. To this end, we propose a full-fledged query interface composed of a TSQL2-like query language with an underlying algebraic framework. The algebraic framework, which is aimed at implementing the query interface on top of a working DBMS, is made up of: (a) the extended temporal algebra TA⋆ supporting OTQs with an hybrid temporal semantics (sequenced and non-sequenced); (b) the continuous temporal algebra CTA that extends TA⋆ with window expressions for CQ specification; (c) the translation of CTA expressions into TA⋆ ones that can be executed by a traditional DBMS with an extended kernel. •Unification of streaming, temporal, and relational querying for advanced analytics.•Full acknowledgment of the inherently temporal nature of streaming data.•Definition of the Continuous Temporal Algebra.•Unified semantics for one-time and continuous queries.•Implementability on standard DBMS technology to leverage on well-founded procedures.