diff --git a/lib/models/graph-object.js b/lib/models/graph-object.js
index <HASH>..<HASH> 100644
--- a/lib/models/graph-object.js
+++ b/lib/models/graph-object.js
@@ -21,6 +21,7 @@ function GraphModelFactory (Model) {
             instanceId: {
                 type: 'string',
                 required: true,
+                unique: true,
                 uuidv4: true
             },
             context: {
adding unique constraint to graph object instance id