public static void UpdateCustomer() { Console.Clear(); Console.WriteLine("ClientID:"); int clientID = int.Parse(Console.ReadLine()); while (clientID.ToString() == "") { clientID = int.Parse(Console.ReadLine()); } Console.WriteLine("Client Name:"); string name = Console.ReadLine(); while (name == "") { name = Console.ReadLine(); } Console.WriteLine("Birth Date:"); string birthDate = Console.ReadLine(); Console.WriteLine("ZIP:"); string zip = Console.ReadLine(); while (zip == "") { zip = Console.ReadLine(); } string conString = "Data Source=DESKTOP-MJA5A7T;Initial Catalog=Car Rent;Integrated Security=True"; SqlConnection con = new SqlConnection(conString); con.Open(); if (Register_New_Customer.ClientExist(con, clientID) && Register_New_Customer.ZipValidation(zip) && Register_New_Customer.DataValidation(birthDate)) { SqlCommand addCustomer = new SqlCommand("update Customers set Name=@name, BirthDate=@birthDate, Location=@location where CostumerID=@clientID", con); addCustomer.Parameters.AddWithValue("@clientId", clientID); addCustomer.Parameters.AddWithValue("@name", name); addCustomer.Parameters.AddWithValue("@birthDate", birthDate); addCustomer.Parameters.AddWithValue("@location", zip); SqlDataReader reader = addCustomer.ExecuteReader(); Program.MenuScreen(); } else { Console.WriteLine("invalid data"); } }