diff --git a/core/prisma/migrations/20240529145416_add_forms/migration.sql b/core/prisma/migrations/20240529145416_add_forms/migration.sql
index 7ed67384c..6dc2da0de 100644
--- a/core/prisma/migrations/20240529145416_add_forms/migration.sql
+++ b/core/prisma/migrations/20240529145416_add_forms/migration.sql
@@ -28,3 +28,6 @@ ALTER TABLE "form_inputs" ADD CONSTRAINT "form_inputs_field_id_fkey" FOREIGN KEY
 
 -- AddForeignKey
 ALTER TABLE "form_inputs" ADD CONSTRAINT "form_inputs_form_id_fkey" FOREIGN KEY ("form_id") REFERENCES "forms"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- Only allow one is_submit = true column per form_id
+CREATE UNIQUE INDEX form_inputs_is_submit_unique ON "form_inputs" ("form_id") WHERE "is_submit" = true;
\ No newline at end of file
diff --git a/core/prisma/schema.prisma b/core/prisma/schema.prisma
index 057e42d5f..b6ae6cbe5 100644
--- a/core/prisma/schema.prisma
+++ b/core/prisma/schema.prisma
@@ -386,7 +386,7 @@ model FormInput {
   label    String
   required Boolean
   form     Form     @relation(fields: [formId], references: [id])
-  isSubmit Boolean  @map(name: "is_submit") // TODO: add partial index so only one of these can be true per formId
+  isSubmit Boolean  @map(name: "is_submit") // This column has a unique index preventing multiple rows with isSubmit per formId (core/prisma/migrations/20240529145416_add_forms)
 
   @@map(name: "form_inputs")
 }