A statically typed query language for property graphs

Abstract

Applications that work on network-oriented data often use property graph models. Although their graph data is represented by an object-oriented model, current approaches cannot define statically typed vertex and edge sets. Thus, custom graph operations use untyped input and output sets and cannot exploit crucial concepts like polymorphism. Not only do illegal calling contexts or arguments result in runtime errors or unexpected query results, but also the resulting code tends to be error prone, unclear, and thus hard to maintain. To solve these problems, we extend the property graph model with typed graph classes and open it up to polymorphism. Our approach is an internal domain specific language for graph traversals based on the object-oriented and functional programming language Scala. A case study emphasizes the usability of our framework.