connecting to data base in c#

"server=.\{instance Name};Integrated Security=true;"

class OrderMapper:Imapper
   {
       static public SqlCeConnection Qconnection = new SqlCeConnection();
       static public SqlCeCommand Qcommand = new SqlCeCommand ();
       public void put(object ob)
       {
          // Qconnection.ConnectionString = "Data Source=C:\\Users\\Admin\\Desktop\\New folder\\WindowsFormsApplication2\\WindowsFormsApplication2\\Database1.sdf";
           string str = "Data Source=|DataDirectory|\\Database1.sdf;Persist Security Info=False;";
            Qconnection.ConnectionString = str;
           Qcommand.Connection = Qconnection;
           Qconnection.Open();
           for (int i = 0; i < orderColection.counter1; i++)
           {
               string commandText = "select * from order";
              // string commandText = "INSERT INTO order VALUES(@RID,@amount,@type,@date)";
               Qcommand.CommandText = commandText;
               Qcommand.CommandType = CommandType.Text;

              /* Qcommand.Parameters.AddWithValue("@RID", orderColection.list[i].rep_id);
               Qcommand.Parameters.AddWithValue("@amount", orderColection.list[i].amount);
               Qcommand.Parameters.AddWithValue("@type", orderColection.list[i].type);
               Qcommand.Parameters.AddWithValue("@date", orderColection.list[i].date );*/
               Qcommand.ExecuteNonQuery();
           }
           Qconnection.Close();
       }
       //public object get(int oid)
      // {

       //}
   }