Here is how to use UTL_FILE to detect a file on the OS insead of writing a UNIX or DOS script. The procedure can be scheduled through DBA_JOBS to check for the existence of a file that has been FTP'ed, for example. Once the file has been detected, it calls another procedure to start processing.
REM check_for_file.sql REM Steve Montgomerie REM 26 April 2000 REM REM Use UTL_FILE to detect the presence of an OS file REM like when looking for a file to arrive from REM an FTP process. Once the file is detected call REM another procedure to start processing. REM REM If the file is detected call another procedure REM to start processing or else simply exit the routine. REM REM Typically in the case of FTP two files are sent. The REM dump file and a dummy file. Check for the dummy file REM so as not to process a dump that has not been completly REM transferred. REM REM Schedule this procedure through DBMS_JOBS REM To not process more than once create a small table REM and set a flag that this procedure can check. REM Alternatively use a JAVA stored procedure to delete REM dummy file when it is detected. CREATE OR REPLACE PROCEDURE check_for_file AS file_chk_file UTL_FILE.FILE_TYPE; BEGIN file_chk_file := UTL_FILE.FOPEN ('c:temp', 'dummy.txt', 'R'); -- start_job; Call a procedure to start processing here UTL_FILE.FCLOSE_ALL; EXCEPTION WHEN UTL_FILE.INVALID_OPERATION then RAISE_APPLICATION_ERROR(-20102,'Invalid Operation'); END; /
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This was first published in August 2002