Towards Formal Foundations of Event Queries and Rules
François Bry, Michael Eckert · 2007
The field of complex event processing still lacks formal foundations. In particular, event queries require both declarative and operational semantics. We put forward for discussion a proposal towards formal foundations of event queries that aims at making well-known results from database queries applicable to event queries. Declarative semantics of event queries and rules are given as a model theory with accompanying fixpoint theory. Operational semantics are then obtained by translating the considered queries into relational algebra expressions. We show the suitability of relational algebra for the kind of incremental evaluation usually required for event queries. With the aim of generating further discussion of formal foundations in the research community, we reflect openly upon both strengths and weaknesses of the presented approach. 1.