diff --git a/src/types/common.ts b/src/types/common.ts
index b2dc20d..b4ccf76 100644
--- a/src/types/common.ts
+++ b/src/types/common.ts
@@ -6,7 +6,7 @@ export type OnDeleteAction =
   | "cascade"
   | "restrict"
   | "no action"
-  | "set null"
+  // | "set null" // Not supported in Spanner
   | "set default";
 
 export interface ForeignKeyConfig {