The authors present a new method for creating a graph database schema (GDBS) based on an entity-relationship diagram (ERD) of the application domain, which is mapped to a GDBS in a two-step process. First, the original ERD is adjusted to a semantically equivalent ERD (enabling it to be mapped in step two). In the second step, the adjusted ERD is mapped to a GDBS according to specific rules. The resulting GDBS includes integrity constraints that enrich existing graph databases.