(PL\SQL) Luhn check number generating

Question

If I run a Luhn-formula check on a number sequence, and the return number is 0, the number sequence is valid (not randomly). I have a random number sequence, but I need a Luhn number generator, which return a number. This number should fill out the random number sequence to retun the Luhn-formula check with 0.

How can I create this Luhn number generator as a function?

score 0 · Answer 1 · answered Oct 15 '18 at 15:23

This result is applicable for the number sequences in every length.

CREATE OR REPLACE luhn_num (orig_num IN NUMBER)
RETURN STRING IS
  num_len NUMBER(20) := length(orig_num);
  result_num NUMBER(10);
  i NUMBER(10);
  temp_num NUMBER(10);
  sum_num NUMBER(10) := 0;

BEGIN
  IF MOD(num_len,2) = 0 THEN 
    FOR i IN 1..num_len LOOP
      IF MOD(i,2) = 0 THEN
        IF length(to_number(substr(orig_num,i,1))*2) > 1 THEN
          sum_num :=  sum_num + to_number(substr(to_number(substr(orig_num,i,1))*2,1,1)) + to_number(substr(to_number(substr(orig_num,i,1))*2,2,1));
        ELSE
          sum_num := sum_num + (to_number(substr(orig_num,i,1))*2);
        END IF;
      ELSE
        sum_num := sum_num + to_number(substr(orig_num,i,1));
      END IF;
    END LOOP;
  ELSE
    FOR i IN 1..num_len LOOP
      IF MOD(i,2) <> 0 THEN
        IF length(to_number(substr(orig_num,i,1))*2) > 1 THEN
          sum_num :=  sum_num + to_number(substr(to_number(substr(orig_num,i,1))*2,1,1)) + to_number(substr(to_number(substr(orig_num,i,1))*2,2,1));
        ELSE
          sum_num := sum_num + (to_number(substr(orig_num,i,1))*2);
        END IF;
      ELSE
        sum_num := sum_num + to_number(substr(orig_num,i,1));
      END IF;
    END LOOP;
  END IF;

  temp_num := 10 - to_number(substr(sum_num,length(sum_num),1));

  IF temp_num = 10 THEN
    result_num := 0;
  ELSE
    result_num := temp_num;
  END IF;

  RETURN result_num ;
END;

(PL\SQL) Luhn check number generating

1 Answers1