mytodate.sf

OReilly Oracle PL SQL Programming第4版源代码

/* Formatted on 2001/12/26 15:20 (Formatter Plus v4.5.2) */
CREATE OR REPLACE FUNCTION my_to_date (value_in IN VARCHAR2)
   RETURN DATE
IS
   TYPE mask_t IS TABLE OF VARCHAR2 (30)
      INDEX BY BINARY_INTEGER;

   fmts             mask_t;
   retval           DATE    := NULL;
   /* Loop index for the scan through the masks */
   mask_index       INTEGER := 1;
   /* Boolean to terminate loop if date was converted */
   date_converted   BOOLEAN := FALSE;

   PROCEDURE init_fmts
   IS
   BEGIN
      fmts (1) := 'DD-MON-RR';
      fmts (2) := 'DD-MON-YYYY';
      fmts (3) := 'DD-MON';
      fmts (4) := 'MM/DD';
      fmts (5) := 'MM/RR';
      fmts (6) := 'MMDDRR';
      fmts (7) := 'MM/YYYY';
      fmts (8) := 'MM/DD/RR';
      fmts (9) := 'MM/DD/YYYY';
      fmts (10) := 'MMDDYYYY';
      fmts (11) := 'YYYYMMDD';
      fmts (12) := 'RRMMDD';
   END;
BEGIN
   init_fmts;

   WHILE  mask_index IS NOT NULL AND NOT date_converted
   LOOP
      BEGIN
         /* Try to convert string using mask in table row */
         retval := TO_DATE (value_in, fmts (mask_index));
         date_converted := TRUE;
      EXCEPTION
         WHEN OTHERS
         THEN
            mask_index := fmts.NEXT (mask_index);

            IF mask_index IS NULL
            THEN
               RAISE;
            END IF;
      END;
   END LOOP;

   RETURN retval;
END my_to_date;
/


/*======================================================================
| Supplement to the third edition of Oracle PL/SQL Programming by Steven
| Feuerstein with Bill Pribyl, Copyright (c) 1997-2002 O'Reilly &
| Associates, Inc. To submit corrections or find more code samples visit
| http://www.oreilly.com/catalog/oraclep3/
*/