private static void CreateCommand(string queryString,
    string connectionString)
{
    using (SqlConnection connection = new SqlConnection(
               connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        command.Connection.Open();
        command.ExecuteNonQuery();
    }
}

//引入命名空间
using System;
using System.Data.SqlClient;

class MainClass 
{
  static void Main(string[] args)
  {
    SqlConnection MyConnection = new SqlConnection("Data Source=(local); Initial  Catalog = MyDatabase; User ID=sa;Password=");

    MyConnection.Open();
  }
}