initial

backend/src/main/java/com/mycompany/backend/demo/data/DataServiceImpl.java

@@ -57,5 +57,10 @@ public class DataServiceImpl implements DataService {
     @Override
     public void deleteType(String id) {
         dataTypes.remove(id);
+        // 1. Do other stuff here, e.g. update the related objects.
+        //    This part must be performed in a single transaction
+
+        // other methods
+
     }
 }