diff --git a/db/versions/11230-brownEucalyptus/00-addClientObservationType.sql b/db/versions/11230-brownEucalyptus/00-addClientObservationType.sql
index b4486f9d4..935758b8d 100644
--- a/db/versions/11230-brownEucalyptus/00-addClientObservationType.sql
+++ b/db/versions/11230-brownEucalyptus/00-addClientObservationType.sql
@@ -1,2 +1,2 @@
-ALTER TABLE vn.clientObservation ADD COLUMN IF NOT EXISTS observationTypeFk TINYINT(3) UNSIGNED NOT NULL;
+ALTER TABLE vn.clientObservation ADD COLUMN IF NOT EXISTS observationTypeFk TINYINT(3) UNSIGNED NULL;
 ALTER TABLE vn.clientObservation ADD CONSTRAINT clientObservationTypeFk FOREIGN KEY IF NOT EXISTS (observationTypeFk) REFERENCES vn.observationType(id);