  Amazon Neptune is a graph database service that supports two graph
(meta)models: W3C's Resource Description Framework (RDF) and Labeled Property
Graphs (LPG). Customers opt in for one or the other model, and this choice
determines which data modeling features can be used, and - perhaps more
importantly - which query languages are available to query and manipulate the
graph. The choice between the two technology stacks is difficult and requires
consideration of data modeling aspects, query language features, their adequacy
for current and future use cases, as well as many other factors (including
developer preferences). Sometimes we see customers make the wrong choice with
no easy way to reverse it later.
  It is therefore highly desirable that the choice of the query language can be
made without consideration of what graph model is chosen, and can be easily
revised or complemented at a later point. In this paper, we advocate and
explore the idea of a single, unified graph data model that embraces both RDF
and LPGs, and naturally supports different graph query languages on top. We
investigate obstacles towards unifying the two graph data models, and propose
an initial unifying model, dubbed "one graph" ("1G" for short), as the basis
for moving forward.
