PostgraphQL generates a GraphQL API from a PostgreSQL database. It won't change how your data is modeled or queried at the database level, i.e., it is NOT a graph database project like Agens, Neo4j, Cayley, etc.
This isn't a graph database, it's GraphQL which is an (unfortunately named) interface or "language" to query data, regardless of what the underlying database or data model is.
