Implementation Strategies for Views over Property Graphs

The need to query complex interactions and relationships has motivated interest in property graph database platforms. For some graph applications, graph views are required to abstract the data, e.g., to capture individual-level vs. organization-level relationships; or show single computational steps vs. composite workflows. Emerging efforts to standardize graph query languages have developed semantics and language constructs for graph views. This paper considers the task of implementing such views using rewriting techniques --- both using existing property graph DBMSs and converting to relational RDBMSs. We consider both virtual and materialized views, ways of rewriting queries, and structures for indexing data. We also note a common use case of graph views, which involves preserving a graph except minor local transformations; we develop novel extensions and semantics for this. We evaluate and compare the performance of our techniques under a variety of workloads, and we compare existing graph and relational DBMS platforms.