Thanks a lot guys
I followed pbreits advice and just got rid of the computed fields,
doing it instead in the controller. Much more elegant.
To D Villas - I like your framework more than mine, but at the moment
I'm working on 'minimum specs', I'll come back to yours when I
actually understand the basic coding! (ie phase 2)
All the best
Rob
On May 6, 2:05 am, villas <villa...@gmail.com> wrote:
> HiHappyRob,
>
> If you want this to be flexible, I guess you would need something
> more like this:
>
> entrants: id, name
> exams: id, descr
> exam_entry: exam_id, entrant_id, total_scrore
> questions: id, exam_id, question_num, question_text
> options: id, question_id, option_text, score
> answers: id, exam_entry_id, option_id
>
> It is important to try not to compromise on your data structure. It
> may be more difficult to display the forms and process them, but
> usually you win in the long run by 'normalising' your data as much as
> possible.
>
> Best wishes, D
>
> On May 4, 12:44 pm,HappyRob<happy.rob.ang...@gmail.com> wrote:
>
>
>
>
>
>
>
> > Computed fields from multiple columns
> > I'm new to programming and have a question
> > How can I make a computed field that adds up from another table
> > depending on the contents of the first table?
> > eg A multi choice exam has the results entered by formfactory.
> > The answers and their scores are stored in a separate table
>
> > db
> > table:answers
> > answers.question, answers.answer, answers.score
> > 1. 3rd planet, a. mars, 0
> > 1. 3rd planet, b. Earth, 10
> > 1. 3rd planet, c. Pluto, 0
> > 2. Best movie, a. Toy Story 3, 5
> > 2. Best movie, b. Casablanka, 10
> > 3. Best movie, c. Twilight, -1000
>
> > db
> > table:exam
> > exam.id exam.name exam.score exam.question01 exam.question02
> > 1 Fred Smith 20 b. Earth
> > b.Casablanka
> > 2 Sarah Smith 15 b. Earth
> > a.Toy Story 3
>
> > As can be seen, the exam score is the sum of the answer scores given.
>
> > My difficulty is in the model...
>
> > m = DAL ('sqlite://storage.sqlite')
> > from gluon.tools import *
> > crud = Crud(globals(),m)
> > m.define_table('answers',
> > Field('question'),
> > Field('answer'),
> > Field('score',int))
>
> > m.define_table('exam',
> > Field('name'),
>
> > Field('score',compute=lambda
> > r:m(m.answers.answer==r.question01).select()[0].score
>
> > +m(m.answers.answer==r.question02).select()[0].score),
> > Field('question01'),
> > Field('question02'))
>
> > It reads the score quite well if checking only one question, but if
> > adding both, it returns None.
> > How could I modify it to add up from multiple questions?
> > You help is greatly appreciated.
