diff --git a/NorthwindCRUD/Models/Contracts/IOrder.cs b/NorthwindCRUD/Models/Contracts/IOrder.cs
index 0925d4c..2ef34b2 100644
--- a/NorthwindCRUD/Models/Contracts/IOrder.cs
+++ b/NorthwindCRUD/Models/Contracts/IOrder.cs
@@ -7,7 +7,7 @@ public interface IOrder
     {
         int OrderId { get; set; }
 
-        string CustomerId { get; set; }
+        string? CustomerId { get; set; }
 
         int EmployeeId { get; set; }