Oracle data retrive via C# application - ASP.net/ Oracle

internal static DataTable getAutoCADDrawings()
        {            DataTable dtTable = new DataTable();
            dtTable = null;
            try
            {
               Database db = DatabaseFactory.CreateDatabase("oracle_db");
               string oraCommand = "SELECT SD.SITEID," +
                    " (SELECT SITENAME FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) as SITENAME ," +
                    " (SELECT SITEOWNER FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) as SITEOWNER ," +
                    " (SELECT SITETYPE FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) AS SITETYPE ," +
                    " (SELECT DISTRICT FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) AS DISTRICT ," +
                    " (SELECT PROVINCE FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) AS REGION ," +
                    " (SELECT STATUSS FROM SITEGENERALDETAIL WHERE SITEID=SD.SITEID) AS SITESTATUS ," +
                    "SD.DOCUMENTTYPE AS DOCTYPE ,SD.DOCUMENTNAME AS DOCNAME ,SD.DOCUMENTNAME AS REMARKS ," +
                    "SD.CREATEDBY AS CREATEDBY,TO_CHAR(SD.RECORDCREATEDDATE,'dd-Mon-yyyy') AS CREATEDDATE ," +
                    "SD.EDITEDBY AS UPDATEDBY,TO_CHAR(SD.RECORDUPDATEDDATE,'dd-Mon-yyyy')AS UPDATEDDATE " +
                "FROM SITEDOCUMENTS SD "+
                "WHERE LOWER(FILEEXTEN) in ('dwg','bak','dwt','dwf') ";
               
                OracleCommand ora = new OracleCommand(oraCommand);
                dtTable = db.ExecuteDataSet(ora).Tables[0];

              
            }
            catch (Exception ex)
            {

            }
            return dtTable;
                  }