diff --git a/SUBD_Car_rent/database/Implementation.cs b/SUBD_Car_rent/database/Implementation.cs
index 9f71a21..e9ebca0 100644
--- a/SUBD_Car_rent/database/Implementation.cs
+++ b/SUBD_Car_rent/database/Implementation.cs
@@ -218,7 +218,7 @@ namespace database
         {
             using var conn = GetConnection();
             conn.Open();
-            using var cmd = new NpgsqlCommand("UPDATE rental SET car_id = @CarId, client_id = @ClientId, start_date = '@StartDate', end_date = '@EndDate', cost = @Cost WHERE id = @Id", conn);
+            using var cmd = new NpgsqlCommand("UPDATE rental SET car_id = @CarId, client_id = @ClientId, start_date = @StartDate, end_date = @EndDate, cost = @Cost WHERE id = @Id", conn);
             cmd.Parameters.AddWithValue("@Id", rental.Id);
             cmd.Parameters.AddWithValue("@CarId", rental.CarId);
             cmd.Parameters.AddWithValue("@ClientId", rental.ClientId);