Re: [WWdevel] webwork: problem values getting set to zero

[John J. <jj...@as...>]

This discussion of storing the student's score refers to the 
student-problem field status.  It was not affected by my changes to the 
types of fields in mysql databases - it is still stored as type text 
rather than type int.  (Maybe it should be stored as an int, but that's 
a different question.)

The problem Gavin discovered was with value - the number of points the 
problem is worth.  It is one of several fields currently stored as type 
int, and they probably all will suffer the same difficulty if they are 
override fields for a more global value.  It is a pretty serious bug, so 
I will attempt to fix this as soon as we know which way we want to go.

I think our options are:

    * in all cases, when storing "" in the database, store it as NULL. 
      It will be promoted back when the information is retrieved.  I
      think this is safe.
    * when storing back to the database, only demote "" to NULL if the
      field is of integer type.
    * stop using integer types in the database.


John


Michael Gage wrote:

>
> On Jul 14, 2005, at 12:45 PM, P Gavin LaRose wrote:
>
>>
>> Isn't the distinction between "haven't tried" and "score of zero" also
>> captured by the attempted field in problem_user?  I think if the status
>> codes this also, it's redundant information.
>>
>> Am I making sense?
>> Gavin
>>
> That makes sense to me.  I believe that we tried to eliminate all of 
> the null responses
> when extracting scoring data because we were getting a lot spurious
> "undefined variables" warnings.  We also get a  lot of "non-numeric in 
> comparison" errors
> when sorting, etc. etc. etc.  In any case I think this is why most 
> things are promoted
> from null at least to "" or to 0.
>
> In light of what you have pointed out I suggest that we "insist" that 
> the student score
> be a number.  I believe that blanks are automatically converted to 0, 
> so they would be ok in sorts.
> (I haven't checked this.)  Otherwise we'll need checks in every sort 
> routine as well as other places.
> Use the "attempts" field to determine if the problem hasn't been tried 
> yet.
>
> We may need to fix some assumptions in the grading and scoring 
> packages to conform to this.
> The simplification in sorts that we gain by assuming that score is 
> always a number seems to
> me to outweigh desires for more, occasionally non-numeric states.
>
> Take care,
>
> Mike
>
>
>> On Thu, 14 Jul 2005 at 12:39 Michael Gage wrote:
>>
>>> Could we get a list of what states are needed for the student score?
>>>
>>> number     -- means the student has achieved this score on this problem
>>> 0                --  means the student has tried this problem but
>>> hasn't gotten in correct
>>> null/ blank  -- means that the student hasn't tried the problem.
>>>
>>> Are there are other states we need?
>>>
>>> Do we need the state that distinguishes between "hasn't tried the
>>> problem" and the one where the score is zero?
>>> I think perhaps we do, so that we can warn the student they haven't yet
>>> completed an assignment while not
>>> bugging them about problems that they haven't successfully completed.
>>>
>>> any other thoughts on what is needed?
>>>
>>> Take care,
>>> Mike
>>
>>
>> -- 
>> P. Gavin LaRose, Ph.D.  Program Manager (Instructional Tech.)
>> Math Dept., University of Michigan
>> gl...@um...                        "There's no use in trying," 
>> [Alice]
>> 734.764.6454                             said. "One Can't believe 
>> impossible
>> http://www.math.lsa.umich.edu/~glarose/  things." "I daresay you 
>> haven't had
>>                                          much practice," said the Queen.
>>                                                               - Lewis 
>> Carrol
>>
>
>
>
> -------------------------------------------------------
> SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
> from IBM. Find simple to follow Roadmaps, straightforward articles,
> informative Webcasts and more! Get everything you need to get up to
> speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click
> _______________________________________________
> OpenWeBWorK-Devel mailing list
> Ope...@li...
> https://lists.sourceforge.net/lists/listinfo/openwebwork-devel