Get radio button list order

Question

I am making an online exam project and I am currently able to show choices for each question in random order. I want to control all currently open exam sessions so that each student gets a different order of choices during the time of the exam -- to avoid cheating.
I am thinking the best way is to retrieve choices radio button list items in order and insert them into a table by session and compare order for each new session asking for the same question.
Is this the best practice?
How do I get each item from the list and its order to be able to insert it into a table?
Thank you,
A

Answer 1

lake wrote:
I 'm not much of a math expert but ...
Let's say you have 5 radio choices 0...4, I am going out on a limb here and predicting there
are 120 combinations? (there are 5 choices for the first button, 4 choices for the second, 3 for the third,
2 for the second and 1 for the last?) So I think you could generate a table of permutations
something like this:
http://www.orafaq.com/forum/t/162827/0/
with      test_tab as
         (select 1 digit, 1 rn from dual union all
          select 2 digit, 2 rn from dual union all
          select 3 digit, 3 rn from dual union all
          select 4 digit, 4 rn from dual union all
          select 5 digit, 5 rn from dual
select t1.digit digit1, t2.digit digit2, t3.digit digit3,
t4.digit digit4, t5.digit digit5
from   test_tab t1, test_tab t2, test_tab t3,test_tab t4, test_tab t5
where  t1.rn != t2.rn
and    t1.rn != t3.rn
and    t1.rn != t4.rn
and    t1.rn != t5.rn
and    t2.rn != t3.rn
and    t2.rn != t4.rn
and    t2.rn != t5.rn
and    t3.rn != t4.rn
and    t3.rn != t5.rn
and    t4.rn != t5.rn
/note: I did not test that.
Ok so you would have at least one permutation table per number of radio buttons.
You would need to randomize the order in the table like assign dbms_random.random() to
a column say TMPSEQ and then order by TMPSEQ and assign rownum to some field (to get a nice simple key for the records) So then you need a package in plsql that retains
what was the last key (permuation) that was used. When it hits the max it would reset to 1.
I think you might actually have to create a different table for each question even if two questions
had the same number of choices because it would be possible
under unfortunate circumstances for the counter to be reset precisely at the beginning of another person's
test. which would totally wreck the effect you were going for :-) Now, I have tried this function:
http://www.orafaq.com/forum/mv/msg/162827/480976/0/#msg_480976
As I have choices from 1 to 4 I got 24 rows. Is there a way to separate those values? I want to bind each choice with a number from 1 to 4 and change their order based on the permutation I selected from the table. I think I need a function that returns character at certain position e.g. chatAt(str,i) so it would be like:
for i 1 to 4 loop
if(charAt(str,i)=1) then
Select chid into first_choice from choices where QID=:page_item and choiceNumber=1;
endif; ....other cases.... end loop
That would be my first choice in any permutation.
Is it best to create one SEQ for each question so each session just gets the next value of that question? How do I create SEQ's from PL SQL?
I also need to lock my SEQ to avoid access from multiple sessions at the same time if I wanted to save that SEQ for future use of displaying choices that were available like they were originally shown. Finally I need to return the list of choices in order to my radio LOV which I still don't know how to do! Probably a join between question table and my ordered choices on equal chid?
Edit: Maybe this way:
select TEXT display_value, CHID return_value
from table(order_choices(:P37_QID_ITEM))
Instead of the one shown in my earlier post?
Edited by: Cruncher on Jan 18, 2011 9:22 AM
Edited by: Cruncher on Jan 18, 2011 9:26 AM