diff --git a/migrations/20240309-add-private-chats.sql b/migrations/20240309-add-private-chats.sql
index b72da947a..a50f6facd 100644
--- a/migrations/20240309-add-private-chats.sql
+++ b/migrations/20240309-add-private-chats.sql
@@ -102,3 +102,6 @@ alter table chat_notifications
 
 alter table chat_notifications
     add constraint chat_notifications_chat_fkey foreign key (chat_id) references chats(id);
+
+alter table chat_notifications
+    add constraint chat_notifications_pkey primary key (user_id, chat_message_id);