string _connstr = "Data Source=XXX;User Id=XXXX;Password=XXXXXXX;Integrated Security=no;";
            using (OracleConnection conn = new OracleConnection(_connstr))
            {
                try
                {
                    conn.Open();
                    MessageBox.Show("URA");
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }

                finally
                {
                    conn.Close();
                }
            }