Chèn dữ liệu vào CSDL sử dụng Parameters

using System;
using System.Data;
using System.Data.SqlClient;

class UsingParameters
{
public static void Main()
{
SqlConnection mySqlConnection =new SqlConnection("server=(local)\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");

mySqlConnection.Open();

SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.CommandText =
"INSERT INTO Employee (" +
"  ID, FirstName, LastName" +
") VALUES (" +
"  @ID, @FirstName, @LastName" +
")";

mySqlCommand.Parameters.Add("@ID", SqlDbType.NChar, 2);
mySqlCommand.Parameters.Add("@FirstName", SqlDbType.NVarChar, 10);
mySqlCommand.Parameters.Add("@LastName", SqlDbType.NVarChar, 10);

mySqlCommand.Parameters["@ID"].Value = "9";
mySqlCommand.Parameters["@FirstName"].Value = "New";
mySqlCommand.Parameters["@LastName"].IsNullable = true;
mySqlCommand.Parameters["@LastName"].Value = "New";

mySqlCommand.ExecuteNonQuery();
Console.WriteLine("Successfully added row to Customers table");

mySqlConnection.Close();
}
}