High-Level Declarative Stream Processing

Abstract

High-level declarative stream processing deals with accessing streams via a declarative language such as a logic-based query language–in contrast to a procedural programming language, say. Moreover, the characterisation as highlevel means that the semantics of such a language depends not only on the streams but also on a background knowledge base. This chapter discusses first-order logic rewritability results for STARQL, a query framework that is an instance of highlevel declarative stream processing following the paradigm of ontology-based data access. Though STARQL provides user-friendly abstractions such as a sequencing mechanism for generating small aboxes from a stream, it can be shown that STARQL allows for first-order logic rewritability of queries.