diff --git a/db/migrate/20240820164827_finalize_check_fields.rb b/db/migrate/20240820164827_finalize_check_fields.rb
index da931d9..7ee8082 100644
--- a/db/migrate/20240820164827_finalize_check_fields.rb
+++ b/db/migrate/20240820164827_finalize_check_fields.rb
@@ -1,6 +1,7 @@
 class FinalizeCheckFields < ActiveRecord::Migration[7.2]
   def change
-    add_column :checks, :number, :string
+    add_column :checks, :number, :integer
+    add_index :checks, :number, unique: true
     
     add_column :checks, :name_de, :string
     add_column :checks, :name_en, :string