I wish to extract updated records from an Oracle database using a scheduled PL/SQL based procedure run every 15 minutes. The last updated date/time is stored in a column, I am currently comparing using last_upd > (SYSDATE - 15/1440). However this meand that is the job fails and is re-run, some updated records will be lost. I had the idea of creating an empty file each time the extract was run and somehow using the created time of the file to compare against. Is this possible in PL/SQL ?
Otherwise can I query a file directly if the contents is the last extracted time