The high expressiveness and elasticity of graphs has led to the design of a wealth of graph models and query languages, used by practitioners to model real-world processes. The property graph model and corresponding query languages, such as the widely used Cypher, have become popular in both industry and research. However, real-time data analysis and management is becoming increasingly important for today's businesses, but graph query languages lack the features to handle streaming graph data and their continuous query evaluation.

In this work, we propose Seraph, a Cypher-based language supporting native streaming features within industry-ready property graph query languages. We formally define the Seraph semantics by combining stream processing with property graphs and time-varying relations while treating time as a first-class citizen of the underlying semantics, thus laying a formal foundation necessary for future implementations. We further propose its syntax and showcase the usage of Seraph for emerging graph-based continuous queries of real-world industrial use cases.