private void btnGetEmployeeSalary_Click(object sender, EventArgs e)
        {
            // get all employees ids
            string        sql        = "GetEmployees";
            SqlDataReader dataReader = DatabaseUtility.ExecuteStoredProcedureReader(sql);

            dataReader.Read();
            MessageBox.Show(dataReader[0].ToString());
            dataReader.NextResult();
            string s = string.Empty;

            while (dataReader.Read())
            {
                s += dataReader[0].ToString() + "\n";
            }

            dataReader.Close();
            MessageBox.Show(s);
        }