diff --git a/elementary/monitor/fetchers/models/schema.py b/elementary/monitor/fetchers/models/schema.py
index a1349858b..89a17379d 100644
--- a/elementary/monitor/fetchers/models/schema.py
+++ b/elementary/monitor/fetchers/models/schema.py
@@ -63,7 +63,7 @@ class SnapshotSchema(ArtifactSchema):
     path: str
     patch_path: Optional[str]
     generated_at: str
-    unique_key: str
+    unique_key: Optional[str]
     incremental_strategy: Optional[str]
     table_name: str