<configuration>
  <appSettings>
     <add key="ConnectionString" value="Data Source=ORCL; User ID=usr; Password=pass; Integrated Security=no;" />
  </appSettings>
  </system.web>
</configuration>

            public OracleDataReader getSprPow()
            {
                OracleConnection conn = new OracleConnection(ConfigurationManager.AppSettings["ConnectionString"]);
                OracleCommand cmd = conn.CreateCommand();
....
                conn.Open();
                OracleDataReader Rd = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                return Rd;
            }