[WebMethod(CacheDuration=45)]
  public DataSet GetCustomers()
  {
     SqlConnection conn;
     SqlDataAdapter myDataAdapter;
     DataSet myDataSet;
     string cmdString = "Select * From Customers";
  
     conn = new SqlConnection("Server=localhost;uid=sa;pwd=;database=Northwind");
     myDataAdapter = new SqlDataAdapter(cmdString, conn);
  
     myDataSet = new DataSet();
     myDataAdapter.Fill(myDataSet, "Customers");
  
     return myDataSet;
  }