diff --git a/models/workflow/workflow.go b/models/workflow/workflow.go
index 25f0f0a..59c8cea 100644
--- a/models/workflow/workflow.go
+++ b/models/workflow/workflow.go
@@ -277,11 +277,17 @@ func (d *Workflow) extractResourcePlantUML(line string, resource resources.Resou
 	}
 	graphItem = d.getNewGraphItem(dataName, graphItem, resource)
 
-	d.Graph.Items[graphID.String()] = *graphItem
+	if graphItem != nil {
+		d.Graph.Items[graphID.String()] = *graphItem
+	}
+
 	return varName, graphItem, nil
 }
 
 func (d *Workflow) getNewGraphItem(dataName string, graphItem *graph.GraphItem, resource resources.ResourceInterface) *graph.GraphItem {
+	if resource == nil {
+		return nil
+	}
 	switch dataName {
 	case "Data":
 		d.Datas = append(d.Datas, resource.GetID())