static void Main(string[] args)
        {
            Customer eklenecek = new Customer();
            eklenecek.Country = "Türkiye";
            eklenecek.DateOfBorn = Convert.ToDateTime("1990-03-28");
            eklenecek.FirstName = "Hasan";
            eklenecek.LastName = "Mehmet";
            int customerId = eklenecek.AddCustomer();

            Customer guncellenecek = new Customer();
            guncellenecek.Id = customerId;
            guncellenecek.Country = "Türkiye";
            guncellenecek.DateOfBorn = Convert.ToDateTime("1989-03-28");
            guncellenecek.FirstName = "Hasan";
            guncellenecek.LastName = "Mehmet";
            guncellenecek.UpdateCustomer();

            Customer silinecek = new Customer();
            silinecek.Id = customerId;
            silinecek.RemoveCustomer();

            Customer businessOperation = new Customer();
            int customerCount = businessOperation.GetCustomerCount();
            List<Customer> after1990 = businessOperation.GetCustomerBornAfterDate(new DateTime(1990,01,01));

        }
 public List<Customer> GetCustomerBornAfterDate(DateTime datetime)
 {
     List<Customer> results = null;
     using (SqlConnection conn = new SqlConnection(GetConnectionString()))
     {
         SqlCommand sqlCmd = new SqlCommand();
         sqlCmd.Connection = conn;
         sqlCmd.CommandText = selectAfterDate;
         sqlCmd.Parameters.Add(new SqlParameter("DateOfBorn", datetime));
         conn.Open();
         SqlDataReader reader = sqlCmd.ExecuteReader(CommandBehavior.CloseConnection);
         if (reader.HasRows)
             results = new List<Customer>();
         while (reader.Read())
         {
             Customer cust = new Customer(reader.GetInt32(0),
             reader.GetString(1), reader.GetString(2),
             reader.GetDateTime(3), reader.GetString(4));
             results.Add(cust);
         }
     }
     return results;
 
 }
 public Customer GetCustomerbyId()
 {
     Customer cust = null;
     using (SqlConnection conn = new SqlConnection(GetConnectionString()))
     {
         SqlCommand sqlCmd = new SqlCommand();
         sqlCmd.Connection = conn;
         sqlCmd.CommandText = selectByIdStatement;
         sqlCmd.Parameters.Add(new SqlParameter("Id", Id));
         conn.Open();
         SqlDataReader reader = sqlCmd.ExecuteReader(CommandBehavior.CloseConnection);
         while (reader.Read())
         {
             cust = new Customer();
             cust.Id = reader.GetInt32(0);
             cust.FirstName = reader.GetString(1);
             cust.LastName = reader.GetString(2);
             cust.DateOfBorn = reader.GetDateTime(3);
             cust.Country = reader.GetString(4);
         }
     }
     return cust;
 }